— Why does the boy keep crying?
— It is ______ he has lost his favorite car model.
| A．since | B．so | C．when | D．because |
Nowadays people are more concerned about the environment ___ they live.
| A．what | B．which | C．when | D．where |
____ which university to attend, the girl asked her teacher for advice.
| A．Not knowing | B．Knowing not | C．Not known | D．Known not |
He is so busy. He cannot afford enough time with his son ____he wants to.
| A．even if | B．as if | C．because | D．before |
____you said at the meeting describes a bright future for the company.
| A．When | B．How | C．What | D．That |
--Why are your eyes so red? You _______ have slept well last night.
| A．can't | B．mustn't | C．needn't | D．won't |