by the end of at the end of 后加时间段还是时间点或者都可以

by the end of at the end of 后加时间段还是时间点或者都可以
by the end of at the end of 后加时间段还是时间点或者都可以

by the end of at the end of 后加时间段还是时间点或者都可以
by the end of 是“到.末”的意思,后边跟不同的时间会有不同的含义和用法.
1 跟将来的时间,就用一般将来时,如
By the end of next month,I will finish reading this book.(到下个月末,我将读完这本书）.
2 跟现在的时间,就用现在完成时,如
By the end of this week ,I have written two books .(到这个星期末,我已经写了两本书了）
3 跟过去的时间,用过去完成时
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）
2 at the end of 后边可以跟时间和地点名词,表示“在.末" 如at the end of this month 在这个月末,at the end of last month ,at the end of next month ,at the end of the road 在路的尽头 等