—Someone wants you on the phone.
—________ nobody knows I am here.
A．Although B．And
C．But D．So
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
