Do you think we can get there on time —-Yes，_______ thetruck doesn’t break down

30My parents have promised to come to see me before I _____ for Africa

I don’t believe these people have achieved success__________. They must have put much effort into their work.

You’d better give the task to _____ can finish it ahead of time

How many birds can you see in the trees—I can see _____ birds in them.