The conference aims to develop business and let people think about ______ they can have a positive influence on the planet.
| A．why | B．that | C．what | D．how |
I was glad to meet Jenny again，________I didn’t want to spend all day with her.
| A．but | B．and |
| C．so | D．or |
There’s no way of knowing why one man makes an important discovery________another man，also intelligent，fails.
| A．since | B．if |
| C．as | D．while |
I have heard a lot of good things about you________I came back from abroad.
| A．since | B．until |
| C．before | D．when |
She says that she’ll have to close the shop________business improves.
| A．if | B．unless |
| C．after | D．when |
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 |