Their sudden attack made us more ________ of the danger around us.
| A．familiar | B．particular | C．aware | D．doubtful |
---Isn’t it a surprise that I happened to meet Francis Mathews at the Christmas Party last week?
---If my memory serves me correctly, you _____ each other for exactly two years.
| A．hadn’t seen | B．haven’t seen | C．didn’t see | D．don’t see |
When it______air pollution, Beijing faces the three “C” s-----cars，coal and construction，which lead to Beijing's thick air pollution.
| A．refers to | B．comes to | C．happens to | D．speaks to |
______ it have been the failure to pick up directions from the ground control that caused the air crash?
| A．Must | B．Could | C．Would | D．Should |
The one concern for parents and students is _______ the student pursues their university education in a foreign country, the student will not have the opportunity to establish social contacts in China.
| A．that | B．that if | C．whether | D．how |
After the quarrel, I tried all my best to fix the misunderstanding between us, but all my efforts seemed _____.
| A．in trouble | B．in case | C．in effect | D．in vain |