_______ they are seeing great development, they are still poorer than many countries in other parts of the world.
| A．Unless | B．Since | C．While | D．As |
The _______ boy made the police and his family _______.
| A．gone; puzzled | B．missing; puzzled |
| C．missing; puzzling | D．lost; puzzling |
He did not go to school yesterday ___________the heavy rain.
| A．because | B．because of |
| C．for that | D．why |
Tom has gone to Shanghai,_____ is in the east of China.
| A．where | B．who | C．which | D．that |
__ he is young, he knows a lot.
| A．Through | B．As | C．While | D．Due to |
I used to use English a lot and spent an hour each day _____ English books in the library.
| A．reading | B．to read | C．read | D．reads |