----How unhappy your roommate looks!----Yes，but he’s not willing to tell me what it is____ is troubling him.
#85453
A
what
B
which
C
as
D
that
推荐题目
It is these poisonous products_____can cause the symptoms of the flu , such as headache and aching muscles .
#85457
A
who
B
that
C
how
D
what
It was in the lab ______ was taken charge of by Professor Harris _______ they did the experiment.
#84771
A
which, that
B
that, where
C
where, that
D
which, where
It was about 600 years ago _______ the first clock with a face and an hour hand was made.
#85210
A
that
B
until
C
before
D
when