—Is there any vaccine(疫苗) against H1N1 flu that can be used on humans?—No, but scientists are working to develop ________ .
#16397
A
that
B
it
C
one
D
so
推荐题目
As a matter of fact, ____is not failure itself, but what we think of failure and what to do afterwards that counts.
#15651
A
this
B
that
C
there
D
it
____ is to be done is ______ to carry it out smoothly since the decision has been made．
#15482
A
What; how
B
Where; how
C
When; what
D
Where; what
—Silly me! I forget what my luggage looks like.—What do you think of _____over there?
#15270
A
the one
B
this
C
it
D
that