—May I smoke here? —If you _____, choose a seat in the smoking section.
| A．should | B．could | C．may | D．must |
AIDS is said the biggest health to people in that area over the past few years.
| A．that is | B．to be | C．that it has been | D．to have been |
With a lot of problems ________, the newly – elected headmaster is having a hard time.
| A．settled | B．settling | C．to settle | D．being settled |
Soon after getting off his horse, the man appeared at the second storey windows, __he could see nothing but trees.
| A．from which | B．from where | C．in where | D．which |
Tom was very angry about ________ to Mary’s birthday party.
| A．not inviting | B．being not invited | C．not being invited | D．not to be invited |
You can come here to ask me _____ if you have any questions.
| A．at one time | B．at your time | C．at any time | D．all the time |