Keys _______ opening the lock in the door.
| A．used for | B．are used | C．are used to | D．are used for |
—I have never been to the Great wall.
—If you have an opportunity _______ there, you must take it.
| A．to go | B．to going | C．going | D．go |
There was _____ woman in the room, sitting and looking at me in the dark.
| A．a 80-year-old | B．an 80-year-old | C．a 80-years-old | D．an 80-years-old |
-----_______good time we had at the party last night!
-----Yes. It was________ exciting party that I would never forget it.
A. What a; such an B. How ; such C. What; so
.He said that he____________ to Canada a few years ago.
A. had been to B. have been to C. went