More than 1900 people in Africa have _______ the Ebola virus now and there is still no medicine_____ Ebola.
| A．dead of; for | B．died of; against |
| C．dead from; against | D．died from; to |
You will fail the exam ________ you work hard.
| A．unless | B．once | C．since | D．after |
Zhou Libo is Shanghai's favorite funny man. He is good at making people laugh. His lively shows were ________ hot that tickets were sold out in minutes.
| A．very | B．too | C．such | D．so |
I really enjoyed your speech，________ there were some parts I didn't quite understand.
| A．because | B．for | C．until | D．though |
I enjoy fresh air so I always let the window open ________ it is really cold.
| A．unless | B．when | C．if | D．since |
We will have no water to drink ________ we don't protect the earth.
| A．until | B．before | C．though | D．if |