_____ a certain doubt among the workers as to whether he could finish the task in a short time．
#34562
A
It was
B
There had
C
There existed
D
It had
推荐题目
Nowadays the belief has become common ______ sea food and fruit rich in vitamin C should never be eaten at the same meal.
#33304
A
that
B
how
C
when
D
/
The new system needs to be in operation for five months ________ it can be updated.
#30274
A
as
B
while
C
before
D
once
Dr. Black comes from either Oxford or Cambridge. I can’t remember _____.
#30800
A
who
B
there
C
which
D
what