Scientists also have no idea how long it will be before all wild animals in the cages _____. 
#99827
A
should be set free
B
will be set free
C
are set free
D
would be set free
推荐题目
----Why didn’t you go to the concert ?-----I ____a game between two American basketball teams
#101079
A
watched
B
had watched
C
was watching
D
had been watching
I’ve won a holiday for two days to Florida. I ______ my mum.
#104394
A
am taking
B
have taken
C
take
D
will have taken
— I _______ the dishes for over a week. It’s your turn.— I ______ you would say something like that.
#99838
A
have washed; have known
B
have been washing; knew
C
have washed; know
D
have been washing; know
 Hurry up! The train _______. You know it _______at 10:00pm.
#100018
A
leaves; leaves
B
is leaving; leaves
C
leaves; is leaving
D
is leaving; is leaving