Edward, you play so well. But I you played the piano.
| A．didn’t know | B．hadn’t known |
| C．don’t know | D．haven’t known |
What is known to all is that up to now China has made a great___________ to preserving the peace.
| A．conclusion | B．comment |
| C．campaign | D．contribution |
---Did you remember to take the key to Tom?
---Yes, I gave it to him ________ I saw him.
| A．while | B．once | C．suddenly | D．the first time |
It is ________ world of wonders, ________ world where anything can happen.
| A．a; a | B．a; the | C．the; the | D．the; a |
Father ________ for London on business upon my arrival, so I didn’t see him.
| A．has left | B．left | C．had left | D．was leaving |
The boy’s dream was to have his own laboratory ________ to try out some of his own ideas.
| A．from which | B．in which |
| C．by which | D．at which |