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
That piece of music sounds quite familiar. Who _____ the piano upstairs?
#102640
A
as played
B
played
C
plays
D
is playing
I need to go back home before I _________ money.
#102744
A
is running out
B
run out
C
have run out of
D
is running out of
“Are you going to the super market?” “ No,_____.”
#103896
A
I cycle there
B
I walk there
C
to the work
D
I’ve already been there
When I got there, the meeting _____ for ten minutes.
#102051
A
has been on
B
had begun
C
had been on
D
has begun
--- An ant has two stomachs --- one for itself, one for others.--- Really? Quite interesting. I ____ anything about it.
#103271
A
don’t know
B
have known
C
haven’t known
D
didn’t know