— has your friend been to the Great Wall?—Twice.
| A．How often | B．What time | C．How long | D．How many times |
Don’t forget ____ the pen ____ him.
| A．to return, to | B．to return, for | C．returning, to | D．returning, for |
--- What is he doing for vacation?-- He’s _______________.
| A．going camp | B．go camp | C．go camping | D．going camping |
I think walking is________ our health.
| A．good at | B．bad at | C．well in | D．good for |
We're tired because we have ________ yin.
| A．too many | B．too much | C．many too | D．much too |
Do you think ________ necessary to take the second turning?
| A．him | B．it | C．I | D．that |