This nationwide smog should serve as a reminder to all, indicating a high time that we____ on what we've done to the environment.
| A．have reflected | B．are reflecting |
| C．will reflect | D．reflected |
. Knowledge is there for _______ will seek it.
| A．who | B．whoever | C．whom | D．whomever |
―Why are we supposed to buy that flat?
―Because it’s clean and well-located, but _______ of all, it’s affordable.
| A．well | B．good | C．best | D．better |
It came as_______ surprise that Poland’s President and scores of its top officials were killed in _______ air crash in Russia.
| A．不填; the | B．a; an | C．a; 不填 | D．the; an |
. ―Thanks for the ride home!
―_______
| A．Don’t mention it. | B．With pleasure. |
| C．Never mind about that. | D．That’s right. |
The expo is being held in Shanghai, _______a lot of advanced technology is shown for the first time.
| A．why | B．which | C．when | D．where |