Not until all the fish died in the river how serious the problem of water pollution was.
| A．did they realize | B．they did realize | C．had they realized | D．they had realized |
29．It is required in a recent study suggesting the importance of teenagers’ communication with other children of the same age.
| A．interfere | B．interferes | C．can interfere | D．is to interfere |
28．—You must be tired after the flight. You’d better take a good rest.
—Yes, I _________. Thank you.
| A．will | B．should | C．may | D．Would |
27．—Oh, how depressed! I am bound to lose to him in tomorrow’s competition.
—Cheer up! In fact, he is___________than you!
| A．not more nervous | B．no more nervous |
| C．no less nervous | D．a little less nervous |
26．—You look quite tired.
—I __________ the project here in order to meet the deadline.
| A．have done | B．did | C．had done | D．have been doing |
25．Children often form some bad habits, ____________remain with them as ling as they live.
| A．some of them | B．some of which | C．any of them | D．any of which |