His father began to work _______his childhood.A.since B,as early as C,while 为什么选B,这道题和下面的句子有什么不同Since her childhood,she has always tried her best to live up to her ideas.
问题描述：
His father began to work _______his childhood.A.since B,as early as C,while
为什么选B,这道题和下面的句子有什么不同
Since her childhood,she has always tried her best to live up to her ideas.
答
since可以看做完成时的标志,题目中没有明显的完成时态