by加将来时间点 用什么时态

by加将来时间点 用什么时态

by经常是与完成时联系在一起，具体什么完成时取决于by之后的时间，例如by 2013是过去完成时，by now是现在完成时，by 2015是将来完成时

by＋时间”与动作性强的动词连用时，主句多用于完成式。by 后的时间可指现在、 过去或将来时间点。如： By the time he was fourteen years old, he had learned maths all by himself. 到14岁的时候，他就已经自学了数学[SB 2B p.2]。I shall have finished it by the time you come back.你回来以前我就把它做完了[1]。By the end of the match, they had kicked two goals and we had kicked four. [JB p91] 比赛结束时，他们踢进了2分我们踢了4分。They must have finished their work by this time.他们现在一定已经完成工作了[2]。 但是，上述情况中当时间为将来时，主句动作发生在从句动作之后时，主句动词可用一般时态。如：If you're not better by then, I'll take you to see the doctor. [JB3 p.85] 如果到那时还不好些，我就带你去看病。Can you finish this by tomorrow? 在明天以前你能做完这件事吗[1]？ 间或有用进行式的。如：By the end of the first week the head of the department was saying very nice things about me. 第一周末时系主任给我多多美言了几句 [3]。

过去式追答过去将来式

给个例子吧。。。

将来完成时