17．—Is there any better way to help my son get rid of the habit of playing computer games?
—To tell you the truth, it’s very hard. But we_______on this problem to improve the situation.
| A．were working | B．had worked | C．are working | D．had been working |
A big step____to strengthen China’s health care systems since we launched an effort in 2008.
| A．has been taken | B．is being taken | C．was taken | D．had been taken |
．---Let me help you cross the street.--______! I’m not that old.
| A．Take your time | B．No way | C．Come on | D．Go ahead |
We went into a hall, on_____ walls hung a few pictures of some famous scientists.
| A．its | B．which | C．whose | D．those |
Newly-developed materials for spaceships can _______ extreme weather conditions.
| A．hold | B．support | C．stand | D．compete |
. —Tom, you get dead drunk again!
—_______? It’s none of your business.
| A．So what | B．How come | C．Why not | D．What for |