at the age of 在某一岁数;在……岁时 by the age of 在某一岁数之前;到……岁时 Incredibly he shot a film at the age of 17. 不可置信的是他17岁就拍了部电影. He must learn to be independent by the age of 18. 他18岁前必须学会独立. 你补充的问题答案用by
at the age of 在…岁时 He became a doctor at the age of 27. 他27岁时成了一名医生。 by the age of 到……年龄 By the age of seven he could write beautifully. 他七岁时字就写得很漂亮了。 希望可以帮到你,谢谢~!...