He was about to tell me the secret ＿＿ someone patted him on the shoulder.
A. as B. until C. while D. when
He is the only one of the students who ＿＿ a winner of three years.
A. is B. are C. have been D. has
The scientist did ＿＿ experiments to test the new drug.
A. a series of B. a good many of C. a great many D. a lots of
These plants are watered ＿＿ .
A. every a few days B. every third day
C. every others day D. each two days
Guilin is ＿＿ worth ＿＿. Have you been to it?
A. well; visiting B. well; to visit C. very; a visit D. very; a visit
Do you know a lot of research work ＿＿ in recent years?
A. have been carried out B. has carried out
C. are carried out D. has been carried out
