by the end of 后面接过去时间时，句子的时态通常用过去时态——比如过去完成时、一般过去时、过去进行时等。
相关介绍
用过去完成时
强调在所提及的过去时间之前已完成的动作，句子暗示两个时间：一个是 by the end of 后面的过去时间，另一个是“the end of + 过去时间”之前的时间。
如：By the end of last month, I had planted thousands of trees.
到上个月末，我已经种了数千棵树了。
By the end of last month, he had been robbed at least three times.
到上月底，他已被抢了至少三次。
I’d had a bellyful of his family by the end of the weekend.
到周末的时候，我已经受够了他一家人。
By the end of the day we had sold over 2000 tickets.
那一天下来我们卖出了两千多张票。
By the end of that year Henry had collected more than a thousand foreign stamps.
到那年年底，亨利已收集了一千多张外国邮票。
By the end of the evening she had abandoned all pretence of being interested.
到晚会结束时，她已将假装的兴趣抛得一干二净。
