You can only be sure of _____ you have at present; you cannot be sure of something _____ you might get in the future.
| A．that; what | B．what; 不填 | C．which; that | D．what; which |
So far this year we ______ a fall in house prices by between 5 and 10 percent.
| A．saw | B．see | C．had seen | D．have seen |
I like these English songs and they ________many times on the radio.
| A．taught | B．have taught | C．are taught | D．have been taught |
—Did you see a man in black pass by just now?
—No, sir. I ________ a newspaper.
| A．read | B．was reading | C．would read | D． am reading |
-----Did you watch the basketball match yesterday?
-----Yes, I did. You know, my brother ________ in the match.
| A．is playing | B．was playing | C．has played | D．had played |
Over the past decades, sea ice in the Arctic as a result of global warming.
| A．had decreased | B．decreased | C．has been decreasing | D．is decreasing |