For years, it was viewed as a serious problem, ________ that has never been really solved.
#15139
A
one
B
where
C
it
D
which
推荐题目
The cruelty of the terrorists towards the two Chinese engineers in Pakistan and _____ of the terrorists towards America in September 11, filled everyone with horror.
#16555
A
those
B
that
C
one
D
it
The citizens of Beijing are proud of _______ they have done to make Beijing a beautiful city.
#16270
A
that
B
which
C
what
D
how