— What does the sign over there read?
—“No person __________ smoke or carry a lighted cigarette，cigar or pipe in this area.”
A. will B. may
C. shall D. must
The best times to visit Shangri-la are spring and autumn ____ the temperature is at its mildest.
A. when B. where C. that D. which
Scientists study ____ human brains work to make computers.
A. when B. how C. that D. whether
______ in the school campus in spring, we will always noitce a colorful display of flowers.
A. Walk B. Having walked C. Being walking D. Walking
It’s great that all the visitors who _______ on the island were saved.
A. trapped B. have been trapped C. had trapped D. had been trapped
The operation is _______ success. and the patient is now out of ______ danger.
A. a; the B. / ; / C. / ; the D. a ; /
