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
推荐题目
--- What is that wonderful smell? --- Our neighbor ________ for a party.
#99373
A
have prepared
B
is preparing
C
prepare
D
will prepare
—You haven’t got the textbook for my chemistry yet.—I know, and we ________ to get it for the last five weeks.
#100488
A
will have been trying
B
have been trying
C
will be trying
D
had tried
John kept looking at the pretty girl, wondering whether he_________ her somewhere.
#99831
A
saw
B
has seen
C
sees
D
had seen
No one in the department but Tom and I that the director is going to resign（辞职）.
#103549
A
knows
B
know
C
have known
D
am to know