_________ did the students realize that they were mistaken about spiders.
| A．It was until then | B．It was not until then |
| C．Not until then | D．Not until when |
—How does the Internet ____us?
—By sharing information free of charge．
| A．educate | B．improve | C．limit | D．benefit |
The director asked me to finish this task by Sunday．How can I ____to?
| A．attempt | B．manage | C．decide | D．happen |
The letter Mary had looked forward to ____her last night and she was very excited．
| A．reached | B．reaching ' | C．had reached | D．has reached |
The news shocked the whole nation ____a strong earthquake hit Yushu on Apr．14, 2010．
| A．what | B．when | C．that | D．which |
You ____be tired—you have worked only for ten minutes．
| A．won't | B．mustn't | C．needn't | D．can't |