So sudden ______ that the enemy had no time to escape．
| A．did the attack |
| B．the attack did |
| C．was the attack |
| D．the attack was |
The fact has worried many scientiststhe earth is becoming warmer and wormer．
| A．what | B．that | C．though | D．which |
Do you still remember the rider and his new bike we saw in the street last week?
| A．which | B．who | C．that | D．whom |
Tony the fact that he had made a mistake．
| A．accounted | B．permitted | C．allowed | D．acknowledged |
But for her help，we the task in time．
| A．will not finish | B．had not finished |
| C．can not finish | D．could not have finished |
The guidance booklet can be of great help towants to do the job．
| A．whoever | B．whomever | C．no matter who | D．who |