grammar

[mansoor alam]

How do i know where to use ''may'' and ''might'', ''could'' and ''ought''?

[Snowcake]

You may first try the Grammar Glossary on the left of your post (look up 'modal verbs') I fear this part of grammar is too comprehensive to sum it up in few words.

You can come back here, and try to build some sentence with these verbs so that we can advise you on them.