Polar bears live mostly on_______sea ice,which they use as_______platform for hunting seals.
| A．a;a | B．a;the |
| C．不填;a | D．the;不填 |
．— Has Tom finished his report so far?
— I have no idea．He ______it this morning．
| A．did | B．has done | C．was doing | D．had done |
．Most of the teaching equipment presented by the Hope Project, as well as the books, ______made good use of in the village school．
| A．have | B．has | C．have been | D．has been |
．— Do you happen to have twent
y dollars on you?
—______?
— I want to buy a reference book．
| A．So what | B．Why not | C．How much | D．What for |
．But for the storm, we ______ earlier．
| A．can arrive | B．will arrive | C．had arrived | D．could have arrived |
A good friend of mine from when I was born _______ at my home right before I left for Beijing．
| A．showing up | B．showed up | C．to show up | D．shows up |