23．He is neither European, nor American. He is from Australia.
| A．a; an; 不填 | B．a; an; the | C．a; a; 不填 | D．an; an; 不填 |
. The government has to close those small factories to prevent the water of the river ______.
| A．polluting | B．from polluting | C．being polluted | D．polluted |
If you keep on, you will succeed ________.
| A．in time | B．at one time | C．at the same time | D．on time |
—________ you__________ the editor at the airport?
—No, when we got there, he___________ driven away.
| A．Have; met; has been | B．Did; meet; had been |
| C．Did; met; have been | D．Have; met; was |
Does the way you thought of___________ water clean make any sense?
| A．making | B．how to make | C．to make | D．having made |
—What do you think of his opinion?
—None has given me ___________ piece of advice.
| A．a better | B．a best | C．the best | D．the better |