My friend Jack was the first person I knew ______an iPhone 5S.
| A．using | B．to use | C．used | D．having used |
Jack asked his brother Betty.
| A．did he know | B．if he knows | C．does he know | D．whether he knew |
I have heard from my father, is in American.
| A．which | B．that | C．from whom | D．who |
Swan Lake is a famous ballet(芭蕾) in four acts, ________ on a German fairy tale.
| A．basing | B．based | C．bases | D．to base |
He had no idea of how the climb would be _______ he was half way up the mountain.
| A．when | B．until | C．while | D．as |
—Would you like some more chicken?
—No, thanks. I am ______ a diet and try to ______weight.
| A．on; lose | B．on; put on | C．in; have | D．in; lose |