Some researchers are finding that daydreaming may be important to _____ mental health. Daydreaming, they say, is____ good means of relaxation.
A the, ∕ B ∕, the C∕ , ∕ D ∕, a
We had to be patient because it ________ some time ________ we got the full results.
| A．has been；since | B．had been；until |
| C．was；after | D．would be；before |
He was so deep in thought，thinking of the problem ________ he knocked into the tree without noticing it.
| A．when | B．while |
| C．because | D．that |
________ all of them are strong candidates，only one will be chosen for the post.
(2011·陕西，19)
| A．Since | B．While |
| C．If | D．As |
Please call my secretary to arrange a meeting this afternoon，or________it is convenient to you. (2011·江西，29)
| A．whenever | B．however |
| C．whichever | D．wherever |
Jack wasn’t saying anything，but the teacher smiled at him________he had done something very clever. (2011·湖南，33)
| A．as if | B．in case |
| C．while | D．though |