1、第一句,since 改为 after,since强调持续性,这里是时间点的概念,after更好
2、第二句,"our homework load was too demanding" load 和demanding搭配上不太好,可以很简单的"I have too much homework to do"就行了呗,言简意赅.
3、第三句,"we have many exercises that we can't complete" 逻辑上有问题,老师布置的作业怎么会“不能”完成?是客观上不可以完成,还是因为太多太难而难以完成?可以说的具体一些,比如：Every day,we have too many exercises that we can hardly complete in time.
4、下一句最好不要用 apply for,apply for 是申请的意思,申请是没什么难度的,谁都可以申请,难的是得到一份好工作,所以直接用简单的 get 就行了.而且这句话中的主语里有teachers,也有点问题,teachers 已经有工作了,他们不用再“申请”了吧~