________ there are living creatures in the outer space as those on Earth hasn't been proved until now.
#30306
A
How
B
When
C
Where
D
Whether
推荐题目
Rod is determined to get a seat for the concert________it means standing in a queue all night.
#80187
A
so that
B
however
C
even though
D
as if
The dancers, all of _______ masks came off suddenly, gave us a great surprise.
#32153
A
their
B
whose
C
which
D
whom
Neighbors said they heard the man tell the woman that she couldn’t leave______ she gave back the money borrowed from him.
#30911
A
unless
B
since
C
if
D
though