—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 |
---Is Bob still performing?
---I’m afraid not. He is said _______ the stage already, as he has become an official.
| A．to have left | B．to leave |
| C．to have been left | D．to be left |
_________ the task on time, he was fired by the boss.
| A．Not completed | B．Not having completed |
| C．Not have completed | D．Not being completed |
–Why, Jack! Someone seems to have called you over there. – Yes? I __________ that.
| A．am not realizing | B．haven’t realized |
| C．didn’t realize | D．don’t realize |
After ________ absence of 10 years from his hometown, Mr. Li doesn’t know ________ great changes have taken place there.
| A．an;/ | B．an; the | C．the; a | D．/; the |
–Why don’t we go to the new Sichuan restaurant for a meal?
–___________.
| A．Great! I’ve been expecting that |
| B．Sorry, but I forgot it. |
| C．No, I won’t go for it |
| D．It’s not my pleasure |