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 was glad to meet Jenny again，________I didn’t want to spend all day with her.
| A．but | B．and |
| C．so | D．or |
Don’t turn off the computer before closing all programs，________you could have problems.
| A．or | B．and |
| C．but | D．so |
It’s not easy to change habits，________with awareness and selfcontrol，it is possible.
| A．for | B．or |
| C．but | D．so |
I took my driving license with me on holiday，________I wanted to hire a car.
| A．in case | B．even if |
| C．ever since | D．if only |
________ small，the company has about 1,000 buyers in over 30 countries.
| A．As | B．If |
| C．Although | D．Once |
________we have enough evidence，we can’t win the case.
| A．Once | B．As long as |
| C．Unless | D．Since |
Mark needs to learn Chinese ________ his company is opening a branch in Beijing.
| A．unless | B．until |
| C．although | D．since |
________I have to give a speech，I get extremely nervous before I start.
| A．Whatever | B．Whenever |
| C．Whoever | D．However |
One can always manage to do more things，no matter________full one’s schedule is in life.
| A．how | B．what |
| C．when | D．where |
In the global economy，a new drug for cancer，________ it is discovered，will create many economic possibilities around the world.
| A．whatever | B．whoever |
| C．wherever | D．whichever |
You must learn to consult your feelings and your reason________you reach any decision.
| A．although | B．before |
| C．because | D．unless |
It’s much easier to make friends ________ you have similar interests.
| A．unless | B．when |
| C．even though | D．so that |
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 |
She says that she’ll have to close the shop________business improves.
| A．if | B．unless |
| C．after | D．when |
I have heard a lot of good things about you________I came back from abroad.
| A．since | B．until |
| C．before | D．when |