The difference among May I, Could I and Would I I was wondering which is the most poilte usage for native speakers and when do you use them (in which conditions).

In the universe VS In nature I am quite puzzled because I don't know how to use "the" correctly. I mean I thought universe and nature are just same type of words.

What's the difference between "as long as "and "so long as"? Thank you:)

Last night I went to bed after I did my homework. Can I change "did" into "had done"?

Regularly every summer, Janet fell in love. In my opinion, it's quite strange to use SIMPLE PAST TENSE here. But this is the example given by Practical English Usage. I am puzzled:(

It's probably going to be rain tomorrow morning. Is that right if I change it into "It will be rainning tomorrow morning ."?

So far this week, the teachers have given us a lot of homework every day. Can I change "have given" into "have been giving"?

Thank you for your help.

Last night, I had dinner with two friends. I have known both of them for a long time. Can I change "have known" into "had known"?

My grandpa lived in a small village in Italy when he was a child. Can I change it into "My grandpa had been living in a small village"?