—China develops so fast.
—That’s true. It ______ a lot already.
| A．changes | B．changed | C．will change | D．has changed |
It’s two and a half weeks since the exchange students __________ Wuxi.
| A．arrived | B．reached | C．have been in | D．have arrived in |
Little Tom has got a lot of birthday presents, but he isn’t able to take all of them ___.
| A．on time | B．at a time | C．at same time | D．from time to time |
We can have ___ blue sky if we create ___ less polluted world.
| A．a. a | B．a, the | C．the, a | D．the, the |
-----Did you notice him come in?
-----No. I _____ a football game.
| A．have watched | B．had watched | C．am watching | D．was watching |
You should return the digital camera to Sally ________she will get angry.
| A．so that | B．because | C．before | D．or |