It was quite a serious mistake, ____caused by carelessness. 
#73080
A
which I think was
B
I think which was
C
which I think it was
D
I think which it was
推荐题目
The river, ____ are covered with trees, is very long.
#73086
A
which banks
B
of which banks
C
whose the banks
D
the banks of which
. Could ______ be in the restaurant ______ you lost your handbag?
#70202
A
it; which
B
it; that
C
that; that
D
that; where