Every year he ________ to Beijing to visit his teacher.
#100334
A
have come
B
comes
C
came
D
come
推荐题目
The thief______ when he was stealing a wallet from a woman. 
#104328
A
happenedtonotice
B
wastakenplacetonotice
C
washappenedtobenoticed
D
happenedtobenoticed
New technology ______ to make sure that the cars, taxis, buses and trains we use ______ the air.
#104707
A
is used; not to pollute
B
has used; is not polluted
C
is being used; do not pollute
D
has been used; to pollute