All his attempts to unlock the door were , because he was using the wrong key.
The school ________I studied for only two years was three kilometers away.
After ________ hard, I got a job in a gold mine.
It's helpful to put children in a situation ________ they can see themselves differently.
After visiting China,most of the foreign friends said they would never forget the time ________ they had spent in China.
- Where does Mr. Black Live ? Can you guess? - Sorry , I can’t guess ________.