"by the age of","at the age of"的区别?
问题描述：
"by the age of","at the age of"的区别?
答
by the age of...:是到...岁时,表示的是一个时间段; 如,By the age of 20 you will have been exposed to at least 20,000 hours of television.(到20岁时,你可能花了2万个小时在看电视上面了).at the age of ...:是...