_)I had not believed in falling in love with somebody at first sight_______I met David on Valentine’s Day three years ago.
| A．when | B．unless | C．if | D．before |
—Why don’t we choose that road to save time?
—The bridge to it __________.
| A．has repaired | B．is repaired |
| C．is being repaired | D．will be repaired |
The number of foreign students attending Chinese universities ________ rising steadily since1990.
| A．is | B．are | C．has been | D．have been |
-Why does the Lake smell terrible?
-Because large quantities of water .
| A．have polluted | B．is being polluted | C．has been polluted | D．have been polluted |
Daniel's family their holiday in Huangshan this time next week.
| A．are enjoying | B．are to enjoy |
| C．will enjoy | D．will be enjoying |
With the help of high technology, more and more new substances ______ in the past years.
| A．discovered | B．have discovered |
| C．had been discovered | D．have been discovered |