The family is a cooperative enterprise for which it is difficult to _____ rules, because each family needs to work out its own ways to deal with its own problems.
| A．set up | B．put down | C．keep up | D．lay down |
He must have attended the meeting yesterday,___________ he?
| A．didn't | B．mustn't | C．needn't | D．hasn't |
I was really too busy with my homework and I couldn't help ____________ housework.
| A．doing | B．do | C．did | D．done |
Mary is one of the brightest students who_________ from New York University.
| A．is graduated | B．have graduated |
| C．has graduated | D．are graduated |
Mr. Alcott, headmaster of the school, refused to accept made by the Students' Union.
| A．either | B．neither | C．any | D．none |
Mary is short__________ her brother is very tall.
| A．still | B．nor | C．while | D．when |