---What great fun we had _____ in the river last Sunday!
---Well, let’s go there again next weekend
A. to swim B. swam C. swum D. swimming
I'm afraid that Rare Earth(稀土) will if we continue to waste it．
A. run out B. break out C. come down D. fall down
He made a mistake, but he took action to change the situation________ it got worse.
A. until B. unless C. before D. since
--- Why didn’t you answer my telephone yesterday?
---Sorry. I a bath at that time.
A. took B. take C. am taking D. was taking
---Where is Andy?
--- He________ be in the library. He said he would borrow books in the morning.
A. must B. mustn’t C. need D. needn’t
It is______ of you to rush into the teachers’ office without knocking at the door.
A. friendly B. strict C. impolite D. impossible
