It is important to ________ the latest research. [ ]

It is several years since he ______ ill andhis illness _______ great damage to his health.

Now, young people chat online talk with each other face to face.

s second to none in maths in ourclass, but believe itornot, he _______ passed the last exam

You look worried，Laura.What’s wrong—I have some problems ________ my schoolwork.