She says that she’ll have to close the shop ________ business improves.
| A．if | B．unless | C．after | D．when |
I will lend you the money ____ you pay it back in one month.
| A．on condition that | B．in case |
| C．in order that | D．considering that |
To read Tolstoy (托尔斯泰) and ____ to the nineteenth century Russian literature are two main reasons for my taking Professor White’s course.
| A．to introduce | B．introduce |
| C．introduced | D．to be introduced |
--- Have you ever heard of an American president called Chester A. Arthur?
--- No, and he’s not mentioned in my history book at all. He seems ____.
A. to have been completely forgotten B. having completely forgotten
C. to have completely forgotten D. being completely forgotten
____ I admit the problems are difficult, I don’t agree that they can’t be solved.
| A．Until | B．While | C．As | D．Unless |
---You were out when I dropped in at your house.
--- Oh, I ____ for a friend from England at the airport.
| A．was waiting | B．had waited |
| C．am waiting | D．have waited |