He stepped into the office, _____down and began to fill in the forms.
| A．sitting | B．to sit |
| C．sat | D．having it |
I don’ t mind _____the door.
| A．you open | B．your open |
| C．your opening | D．yours opening |
There are some dangerous fish in the river, and I’ve warned Jack______ here.
| A．not to swim | B．to not swim |
| C．swim not to | D．to swim not to |
The old man _____live with his wife, but now he ______alone after she died.
| A．used to, is used to live |
| B．used to, is used to living |
| C．was used to , used to live |
| D．did used to , is use to live |
I don’t dare ______ in front of the class
.
| A．sing | B．to sing | C．sings | D．singing |
I think _____ should not be allowed to drive.
| A．sixteen years old | B．sixteen-year-old |
| C．sixteen –year-olds | D．sixteen-years-old |