Hello! I ________ you _______ in London. How long have you been here?
| A．don’t know, were | B．hadn’t known ,are |
| C．haven’t known ,are | D．didn’t know, were |
Half the world's population __________ water shortages within 15 years according to the World Bank, just one of many recent alarming reports on the world's fresh water supply.
| A．are suffering |
| B．have been suffered |
| C．will suffer |
| D．were suffered |
It is reported that in our country cities __________ heavy air pollution that is 30 percent above the national standard or higher should try to meet standards by 2030.
| A．suffering |
| B．suffer |
| C．suffered |
| D．are suffering |
-Is it all right if I sit here?
-__________，sir. The seats are for elderly people only.
| A．Better not |
| B．Go ahead |
| C．As you please |
| D．No way |
She knows that as a secretary she must be pleasant and helpful no matter __________ busy she is or what kind of __________ she may be in.
| A．what; mind |
| B．how; mood |
| C．which; form |
| D．how; thought |
He can __________ his breath under the water for five minutes.
| A．keep |
| B．hold |
| C．take |
| D．make |