-If you have time tonight，I’d like to invite you to a ball.
-That’s very nice of you，but are you ____?
| A．free | B．careful | C．serious | D．true |
I think that this meal was well worth ________ was charged for it.
| A．that | B．what | C．which | D．how many |
—The experiment is of particular importance.
—I see. We will carry on with it ________ we can get enough money.
| A．unless | B．though | C．whether | D．until |
When people move to another country, they often try ________ the customs of their native land.
| A．to keep on | B．to keep off |
| C．to keep up | D．keeping up |
Although punctual himself, the professor was quite used ________ late for his lecture.
| A．to have students | B．for students’ being |
| C．for students to be | D．to students’ being |
________ I met her, she was working only in a small factory.
| A．The first time | B．For the first time | C．At the first time | D．At first |