Modal verbs - could have / should have / would have

This clip helps you to understand the use of modal verbs:-could have, should have, would have.

http://learningenglish.voanews.com/a/everyday-grammar-could-have-should-have-would-have/3391128.html

Modal verb use

Here is another site that gives information about modal verb use.

Using modal verbs

Hello everyone here is a link to help you with using modal verbs. You will need to be able to use these verbs in your next assessment Giving an opinion. Good luck. :-)