acknowledge v. 1 承认［I acknowledged that you are right. 我承认你是对的。］2 表示注意到并做出回应［She acknowledged my greeting with smile. 我给她打招呼，她对我笑了笑。］3 对……表示感谢［Have you written to your uncle acknowledge his gift? 你有没有写信给你的叔叔，感谢他送给你的礼物？］

　　ac•knowl•edge ● v. acknowledged, acknowledging

　　acknowledgment or acknowledgement　n. 确认，承认，答谢［The hug she gave me was an acknowledgment of my apology. 她抱了抱我，表示接受我的道歉。］

　　ac•knowl•edg•ment or ac•knowl•edgement ● n. (复) acknowledgments or acknowledgements

　　acne n. 粉刺(一种年轻人常见的皮肤病；小脓疱不断出现在脸部、背部和胸部，病因是皮脂腺堵塞并膨胀)

　　ac•ne ● n.

　　acorn n.橡树果

　　a•corn ● n. (复) acorns

　　acoustic or acoustical a. 1有关声音的，听觉的, 声学的［Acoustic tile is used to deaden sound. 吸音砖用来隔音。］2 不用电子设备放大音量的乐器［an acoustic guitar 感声吉他］

　　a•cous•tic or a•cous•ti•cal ● a.

　　acquaint v. 使熟悉，了解［Acquaint yourself with the facts. 你要了解事实真相。 Are you acquainted with my sister? 你认识我姐姐吗？］

　　ac•quaint ● v. acquainted, acquainting

　　acquaintance n.相识, 熟

　　ac•quaint•ance ● n. (复) acquaintances

　　acquire v. 得到, 获得 ［The museum acquired a very old vase. 这博物馆收藏了一个非常古老的花瓶。］-见词条get 的词汇选择栏。

　　ac•quire ● v. acquired, acquiring

　　acquit v. 宣判无罪［The judge acquitted the suspect. 法官宣判嫌犯无罪。］

　　ac•quit ● v. acquitted, acquitting

　　acre n. 英亩(土地丈量单位，相当于43,560 平方英尺；足球场的面积比一英亩大一点)

　　a•cre ● n. (复) acres

　　acreage n. 英亩数

　　a•cre•age ● n. (复) acreages

　　acrobat n. 杂技演员

　　ac•ro•bat ● n. (复) acrobats