1. next day将来时
the next day一般过去时
2. by the end of +过去的一个时间过去完成时
by the end of +将来的一个时间将来完成时
e.g. By the end of last term, we had already learned 14 lessons.
By the end of next term, we will have learned 28 leassons.
3.once upon a time一般过去时
4. at one/the time 一般过去时
at a time 一般现在时
脑子里先想了这点.