till和by的区别!

问题描述:

till和by的区别!
till和by的区别
还有,星期一之前把这本书还给我 怎么说?

意思 till“直到” by“到……为止”
till 用 将来时 的关键词;by完成时 的关键词
Give back the book to me before Sunday.
You should have given back the book to me by Sunday.