Modal auxiliaries cannot be used without a main verb.

A modal verb doesn't have a past participle.

I really ...... try to get fit.

It's very important to ....  speak more than one language.

Relative pronouns are used to connect a clause or a phrase to another noun or pronoun.

His excuse ..... be true, but I don't believe.

You ....... forget your sun cream. It's going to be very hot!

.... you speak French? - Only a few words, but my Russian is pretty good.

Whose is this bag? - I don't know, but it ..... belong to Annie.

You ....... ....... put your feet on the cafeteria tables.

I'm so hungry I ...... eat a horse!

play / can / instrument / a / you / musical / ?

what / like /  ?  / you / do / after / would / to / class

asked / might / if / he / you / be / him / able / it / do / to

should / more / I / vetegetables / eat / .