It isn't quite _____ that he will be present at the meeting.
| A．sure | B．right | C．exact | D．certain |
Mr. Black is a careful and experienfed engineer, so he is often _____ to finish some challenging tasks.
| A．appreciated | B．approached | C．appointed | D．agreed |
China is a peace-loving country and _____no circumstances _____ first use nuclear weapons.
| A．on; will China | B．on; China will |
| C．under; will China | D．under; China will |
In the past decades, sea ice _____in the Arctic as a result of global warming.
| A．had melted | B．has been melting | C．melted | D．is melting |
In our country the cold weather in the north_____ sharply _____the hot weather in the south.
| A．combines；with | B．relates；to | C．compares；with | D．contrasts；with |
_____of danger in the street at night, she had to go home, with a friend_____ her.
| A．Warned; accompanied |
| B．Warning; accompanying |
| C．Having warned; accompanied |
| D．Having been warned; accompanying |