The zoo keepers is worried because the number of visitors __ smaller and smaller.
#103375
A
become
B
became
C
is becoming
D
have become
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I'm sorry you ______ so long, but it' ll still be some time before Jim gets back．
#101357
A
wait
B
waited
C
had waited
D
have been waiting
The key you have just got the front door.
#102563
A
is used to opening
B
is used to be opened
C
is used to being opened
D
is used to open
Every individual _________ in a continually changing world of experience of which he or she is the center.
#102440
A
exists
B
will exist
C
is existing
D
has existed
They had no sooner arrived at the bus station than the bus .
#100267
A
had left
B
will leave
C
left
D
is leaving
—What’s that unpleasant noise?—Oh, the road before the main gate .
#102240
A
is repairing
B
is being repaired
C
is repaired
D
has been repaired