Defendants and the State argue several assignments of error on appeal. We have carefully considered each assignment and conclude that the Court of Appeals correctly found no error which would entitle defendant Cox to a new trial on the kidnapping *79charge. For the reasons stated below, we reverse the Court of Appeals’ decision awarding a new trial to defendants Covington and Godfrey on the kidnapping charges and reinstate the trial court’s judgment on these charges. We also reverse the Court of Appeals’ opinion finding no error in defendants’ convictions of second degree rape, and remand to the trial court for a new trial for all three defendants on the rape charges.
 By their first assignment of error, defendants contend that the Court of Appeals erred in affirming the trial court’s denial of defendants’ motion to strike the testimony of State’s witnesses Dorothy Newby and Shirley Barnes. Dorothy Newby’s testimony concerning the character of the prosecutrix and defendants’ objections thereto are reported in the record as follows:
“My name is Dorothy Newby, and I am employed as resident director at Elizabeth City State University. I have been employed with the Elizabeth City State University since August of 1970. I reside in Elizabeth City at 1208 Harris Drive. In my capacity as resident director I have had an occasion to become acquainted with the young lady by the name of Angela Pettiford. I did have an occasion from time to time to see Ms. Pettiford at or about the campus during the last school year in 1978-1979.
Q. And I ask you whether or not you had an opportunity and occasion to form some opinion about the character and reputation of Angela Pettiford?
Q. You can answer the question. Did you form some opinion?
Q. And was that opinion based upon the information there on the campus community, or your contact with her on campus?
A. My contact with her on campus.
Q. And what is your opinion as to the character and reputation of Angela Pettiford?
*80A. My opinion is that she is a very nice young lady, and has a very good character.
Cross Examination by Mr. Rosser:
Q. Who have you heard discuss her reputation?
A. I haven’t heard anyone discuss her reputation.
Mr. ROSSER: Move to strike her testimony.
COURT: I didn’t hear your question.
Mr. ROSSER: I asked her who had she heard discuss the reputation of Angela Pettiford, and she said she had heard no one discuss it. And I move to strike the testimony as to her character, and reputation.
COURT: I am Denying your Motion.”
State’s witness Shirley Barnes also testified to the prosecutrix’s character, and stated in pertinent part:
“From my personal observations in and about the campus community I did form an opinion satisfactory to myself as to the character and reputation of Angela Pettiford. As to what my opinion as to her character and reputation is, she is a very nice young lady.
Cross Examination by Mr. Rosser:
Q. Have you heard anyone discuss her character and reputation prior to today?
Mr. ROSSER: Move to strike.
It is the general rule in this jurisdiction that a witness may testify concerning a person’s character only after he qualifies himself by affirmatively indicating that he is familiar with the person’s general character and reputation. A witness who testifies that he does not know the general reputation of the person in question is incompetent to testify as a character witness. State v. Denny, 294 N.C. 294, 240 S.E. 2d 437 (1978); State v. Stegmann, 286 N.C. 638, 213 S.E. 2d 262 (1975), death sentence *81 vacated, 428 U.S. 902, 96 S.Ct. 3203, 49 L.Ed. 2d 1205 (1976); Johnson v. Massengill, 280 N.C. 376, 186 S.E. 2d 168 (1972). The proper procedure for qualifying a character witness was set forth in State v. Hicks, 200 N.C. 539, 540-41, 157 S.E. 851, 852 (1931) as follows:
“The rule is, that when an impeaching or sustaining character witness is called, he should first be asked whether he knows the general reputation and character of the witness or party about which he proposes to testify. This is a preliminary qualifying question which should be answered yes or no. If the witness answer it in the negative, he should be stood aside without further examination. If he reply in the affirmative, thus qualifying himself to speak on the subject of general reputation and character, counsel may then ask him to state what it is.”
It is apparent from the record that neither Dorothy Newby nor Shirley Barnes was properly qualified as a character witness before testifying that Angela Pettiford was “a very nice young lady” of good character. Consequently, their testimony was incompetent and improperly admitted. However, we find that defendants waived their right to object to the testimony by failing to make a prompt, timely objection thereto.
It is axiomatic that an objection to or motion to strike an offer of evidence must be made as soon as the party objecting has an opportunity to discover the objectionable nature thereof. Unless prompt objection is made, the opponent will be held to have waived it. State v. Logner, 297 N.C. 539, 256 S.E. 2d 166 (1979); State v. Banks, 295 N.C. 399, 245 S.E. 2d 743 (1978); State v. Jones, 293 N.C. 413, 238 S.E. 2d 482 (1977). In the present case, no objection was made at the time the objectionable nature of the character witnesses’ testimony became apparent. Defendants first objected to the following question addressed to Dorothy Newby: “And I ask you whether or not you had an opportunity and occasion to form some opinion about the character and reputation of Angela Pettiford?” The trial court correctly overruled defendants’ objection. The question appeared designed to elicit the foundation for the witness’ testimony; there was no indication in the wording of the question that the witness would respond with an inadmissible statement. The objectionable nature of Ms. Newby’s *82testimony was subsequently revealed in her statement to the effect that her opinion of Ms. Pettiford’s character was based upon personal contact with Ms. Pettiford and not from a general knowledge of her reputation on the campus. At this point it became apparent that Ms. Newby was expressing her personal opinion of Ms. Pettiford’s character rather than relating the general opinion held by the community. However, defendants made no objection at this time, therefore they are deemed to have waived it.
The incompetency of Ms. Barnes’ testimony was revealed when she stated that from her personal observations she formed an opinion of Ms. Pettiford’s character. Defendants entered no objection to this statement and allowed the witness to further state her opinion of Ms. Pettiford’s good character. Again, defendants failed to make a timely objection to the evidence and therefore waived their right to contest it. Defendants’ assignment of error is without merit and overruled.
 Defendants argue under their second assignment that the Court of Appeals erred in upholding the trial judge’s decision to overrule their objection to certain testimony given by State’s witness O. L. Wise. Detective Wise, an agent for the State Bureau of Investigation, interviewed Angela Pettiford and took a written statement from her on 8 March 1979. He testified as a corroborating witness, relating in detail Ms. Pettiford’s statements to him concerning the events which transpired on 3 and 4 March 1979. At the end of his lengthy testimony, Detective Wise was asked: “And at any point of time in her statement to you did she say anything different from what she testified to here?” Defendants’ objection to the question was overruled, after which the witness replied, “No, sir.” Defendants maintain that by permitting the witness to answer the question, the trial court allowed him to make a conclusory statement of opinion which invaded the province of the jury.
Ordinarily, opinion testimony from a lay witness is not admissible since it is the province of the jury to draw whatever inferences are warranted by the evidence presented. State v. Phifer, 290 N.C. 203, 225 S.E. 2d 786 (1976), cert. denied, 429 U.S. 1050, 97 S.Ct. 1160, 51 L.Ed. 2d 573 (1977). The testimony objected to in the present case, however, was not opinion testimony but *83Detective Wise’s own personal observations after having interviewed the prosecuting witness and having heard her testimony at trial. Mr. Wise was not expressing an opinion on whether Ms. Pettiford was telling the truth, which was the issue to be decided by the jury; he was merely stating that he did not hear Ms. Pet-tiford make any statement at trial which was inconsistent with her written and verbal statements during a prior interview. The fact that a witness made a prior consistent statement is admissible as evidence tending to strengthen the witness’ credibility. State v. Mayhand, 298 N.C. 418, 259 S.E. 2d 231 (1979); State v. Medley, 295 N.C. 75, 243 S.E. 2d 374 (1978); 1 Stansbury’s North Carolina Evidence § 51 (Brandis Rev. 1973). This evidence is admissible solely for the purpose of corroborating the witness’ testimony, and not as substantive evidence. However, when a defendant fails to specifically request an instruction restricting the use of corroborative testimony, it is not error for the trial judge to admit the evidence without a limiting instruction. State v. Sauls, 291 N.C. 253, 230 S.E. 2d 390 (1976), cert. denied, 431 U.S. 916, 97 S.Ct. 2178, 53 L.Ed. 2d 226 (1977); State v. Sawyer, 283 N.C. 289, 196 S.E. 2d 250 (1973). In the case sub judice, defendants did not request an instruction restricting the use of Detective Wise’s testimony. His testimony was admissible as tending to establish a prior consistent statement by the prosecuting witness and there was no error in its admission without a limiting instruction. In his charge to the jury, the trial judge repeatedly instructed them that they were to be the sole judges of the credibility of each witness, and the sole judges of the weight to be accorded the evidence presented. Defendants have failed to show that they were prejudiced by Detective Wise’s testimony, thus we find no error in its admission and defendants’ second assignment is overruled.
 By their assignments numbered five through eleven, fifteen through seventeen, and twenty-one through twenty-three, defendants allege that the Court of Appeals erred in finding no error in the trial judge’s instructions to the jury concerning the rape charges against them. We find merit in defendants’ allegations and hold that all defendants must be awarded a new trial on the rape charges.
The bills of indictment charging defendants with first degree rape specify that each defendant committed the offense charged *84“on or about the 3rd day of March, 1979, in Pasquotank County.” The State’s evidence tended to show that defendants may have raped Ms. Pettiford on 3 March 1979 in Pasquotank County, and that they did rape her in Virginia and in Rocky Mount, North Carolina on 3 and 4 March 1979. The trial judge summarized the evidence tending to prove all the alleged rapes, and then, as to each defendant, instructed the jury in substance as follows:
“. . . I charge that if you find from the evidence and beyond a reasonable doubt that ... on or about the 3rd or 4th day of March, 1979, the defendant . . . was more than sixteen years of age, and had sexual intercourse with the prosecuting witness without her consent and against her will, or forcibly overcame her resistance or procured her submission by the use of a deadly weapon, it would be your duty to return a verdict of guilty of first degree rape. . . .
I charge that if you find from the evidence and beyond a reasonable doubt that ... on or about the 3rd or 4th day of March, 1979, the defendant . . . overcame Angela Pettiford’s resistance and had sexual intercourse with her without her consent and against her will, it would be your duty to return a verdict of guilty of second degree rape.”
The trial judge at no time instructed the jury that they could only convict defendants, if at all, of first or second degree rape for those incidents which occurred in Pasquotank County.
It is a fundamental rule in the administration of criminal justice that a defendant must be convicted, if at all, of the particular offense charged on the bill of indictment. State v. Best, 292 N.C. 294, 233 S.E. 2d 544 (1973); State v. Watson, 272 N.C. 526, 158 S.E. 2d 334 (1968); State v. Jackson, 218 N.C. 373, 11 S.E. 2d 149 (1940). In the case sub judice, the trial judge’s charge to the jury created a strong possibility that the jury would convict defendants of offenses not stated in the bills of indictment. By not specifying that defendants could be convicted of only those rapes, if any, which occurred in Pasquotank County, the trial judge allowed the jury to consider whether defendants were guilty of the alleged rapes in Virginia and Rocky Mount. Evidence of all the sexual offenses which purportedly took place on 3 and 4 March 1979 was presented to the jury, and without a limiting instruction, there was nothing to prevent them from considering *85defendants’ guilt or innocence on all the offenses for which evidence was admitted. It is impossible to discern from the jury’s verdict where the particular second degree rape for which they found defendants guilty took place. Consequently, we find that the trial judge committed prejudicial error in failing to charge the jury that they could only convict defendants, if at all, of those rapes which occurred in Pasquotank County. That portion of the Court of Appeals’ opinion which found no error in the trial judge’s instructions concerning rape is reversed, and the case is remanded for a new trial for all three defendants on the rape charges.
The State assigns as error that portion of the Court of Appeals’ decision which awarded a new trial to defendants Cov-ington and Godfrey on the kidnapping charges.1 By their assignments numbered thirteen, fourteen, nineteen and twenty, defendants Covington and Godfrey argue that in the event this Court reverses the Court of Appeals’ decision granting them a new trial, they contend that the Court of Appeals erred in affirming the trial court’s denial of their motion for nonsuit on the kidnapping charges and in finding no error in the trial court’s failure to instruct the jury on the law pertaining to aiding and abetting a kidnapping. For the reasons stated below, we reverse the Court of Appeals’ decision awarding a new trial on’ the kidnapping charges and find no merit in defendants’ remaining assignments of error.
 The Court of Appeals granted a new trial on the grounds that the trial court committed prejudicial error in failing to instruct the jury on the law of acting in concert as it applies to kidnapping. At the close of his charge to the jury, the trial judge asked counsel for the defendant and the State if they wished to *86request further instructions. At the State’s behest, the trial judge instructed the jury on the law of acting in concert as follows:
“Members of the Jury, for a person to be guilty of a crime it is not necessary that he himself do all of the acts necessary to constitute the crime. If two or more persons act together with a common purpose to commit rape each of them is held responsible for the acts of the others done in the commission of the rape.”
We fail to understand how the trial judge’s omission of an instruction relating the law of acting in concert to the particular offense of kidnapping could prejudice defendants Covington and Godfrey in any manner.
Under the principle of acting in concert, an individual may be found guilty of an offense if he is “. . . present at the scene of the crime and the evidence is sufficient to show he is acting together with another who does the acts necessary to constitute the crime pursuant to a common plan or purpose to commit the crime.” State v. Joyner, 297 N.C. 349, 357, 255 S.E. 2d 390, 395 (1979). In order to obtain a conviction under this principle, the State need not prove that the defendant committed any act which constitutes an element of the crime with which he is charged. State v. Williams, 299 N.C. 652, 263 S.E. 2d 774 (1980); State v. Joyner, supra. Thus, the burden of proof which the State must meet to obtain a conviction under the principle of acting in concert is less than its burden to prove that a defendant actually committed every element of the offense charged. The trial judge’s failure to instruct the jury in the present case on the law of acting in concert as it relates to kidnapping was therefore beneficial to defendants Covington and Godfrey. In the absence of that instruction, the State had to satisfy the jury that each defendant committed every element of the kidnapping offense in order to obtain a conviction for all three defendants. Had the instruction been given, the jury could have convicted all three defendants of kidnapping if it was satisfied beyond a reasonable doubt that one defendant committed all the elements of kidnapping, while the other two defendants were merely present at the scene and acting with the first defendant according to a common purpose or plan. Since any error by the trial judge in failing to instruct on the law of acting in concert as it pertains to kidnapping was beneficial to defend*87ants Covington and Godfrey, that portion of the Court of Appeals’ opinion which granted these defendants a new trial on the kidnapping charges is overruled. For the same reasons, we also find no prejudice to defendants Covington and Godfrey in the trial court’s failure to instruct the jury on the law concerning aiding and abetting as it relates to kidnapping, and defendants’ assignments numbered fourteen and twenty are overruled.
 We likewise find no merit in Covington’s and Godfrey’s allegations that the Court of Appeals erred in affirming the trial court’s denial of their motion for nonsuit on the kidnapping charges. These defendants argue that the evidence presented was insufficient to sustain their convictions of kidnapping.
In ruling upon defendants’ motion to dismiss on the grounds of insufficient evidence, the trial court is required to interpret the evidence in the light most favorable to the State, drawing all reasonable inferences in the State’s favor. State v. Fletcher, --- N.C. ---, 272 S.E. 2d 859 (1981); State v. King, 299 N.C. 707, 264 S.E. 2d 40 (1980); State v. Bowman, 232 N.C. 374, 61 S.E. 2d 107 (1950). The trial court must determine as a question of law whether the State has offered substantial evidence of defendant’s guilt on every essential element of the crime charged. “Substantial evidence” is that amount of relevant evidence that a reasonable mind might accept as adequate to support a conclusion. State v. Smith, 300 N.C. 71, 265 S.E. 2d 164 (1980); State v. Powell, 299 N.C. 95, 261 S.E. 2d 114 (1980).
Kidnapping is defined by G.S. 14-39 as the unlawful restraint, confinement, or removal of an individual from one place to another, without his consent, for the purpose of:
“(1) Holding such other person for ransom or as a hostage or using such other person as a shield; or
(2) Facilitating the commission of any felony or facilitating flight of any person following the commission of a felony; or
(3) Doing serious bodily harm to or terrorizing the person so confined, restrained or removed or any other person.”
See also State v. Hunter, 299 N.C. 29, 261 S.E. 2d 189 (1980); State v. Fulcher, 294 N.C. 503, 243 S.E. 2d 338 (1978). There is evidence *88in the present case which tends to show that after Ms. Pettiford climbed into the car with the three defendants and defendant Cox refused to follow her instructions, she repeatedly begged all three defendants to take her back to the Elizabeth City State University campus. Neither defendant Covington nor defendant Godfrey made any effort to aid Ms. Pettiford or to suggest to Cox that he return to the University campus. Ms. Pettiford testified that all three defendants told her they would eventually take her back to Elizabeth City if she cooperated with them, and threatened to harm her if she did not cooperate. She stated that defendant God-frey threatened her with a butcher knife. There is much evidence to suggest that all three defendants repeatedly raped Ms. Petti-ford over a period of two days, during which time she repeatedly asked to be allowed to return to Elizabeth City. After considering this evidence in the light most favorable to the State, we find that there was substantial evidence presented to indicate that each defendant unlawfully confined or restrained Ms. Pettiford against her will, for the purpose of committing the felony of rape. The determination of defendants’ guilt or innocence was therefore a question to be answered by the jury, and the trial court properly denied defendants’ motion to dismiss for insufficiency of the evidence.
We have carefully considered assignments of error numbered twelve and eighteen, presented by defendants Covington and Godfrey, and hold them without merit and overruled.
For the foregoing reasons, that portion of the Court of Appeals’ opinion which found no error in defendant Cox’s conviction of kidnapping is affirmed. We hold that defendants Covington and Godfrey received a fair trial free from prejudicial error on the kidnapping charges, therefore we reverse the Court of Appeals’ decision awarding a new trial to these two defendants, and reinstate the trial court’s judgment on the kidnapping offenses. That portion of the Court of Appeals’ opinion which found no error in defendants’ convictions of second degree rape is reversed, and the case remanded to the trial court for a new trial for all three defendants on the rape charges.
Affirmed in part, reversed in part, and remanded.