It is a common in the USA that you should make an appointment if you want to see a doctor.
| A．rule |
| B．sense |
| C．practice |
| D．habit |
The stone on the river bank rolled under her feet； she was _____into the river，and she called out for help.
| A．being jumped | B．jumped | C．pulled | D．being pulled |
-What do you do yesterday afternoon?
-I went to the bookstore，___ some books and visited my uncle.
| A．to buy | B．bought | C．Buy | D．buying |
Exercise is ______ as any other to lose unwanted weight.
| A．so useful a way | B．as a useful way |
| C．as useful a way | D．such useful way |
-Do you think we can get there on time?
-Yes，_______ the truck doesn’t break down.
| A．even if | B．unless | C．until | D．so long as |
The new machine，if _________ properly，will work at least ten years.
| A．use | B．using | C．being used | D．used |