If the machine makes a mistake -- ____ rarely happens -- it gives a warning in the form of a red light.
#77412
A
that
B
which
C
as
D
what
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---What do you think of teaching , Bob？ ---I find it fun and challenging. It is a job ___you are doing something serious but interesting
#76858
A
where
B
which
C
when
D
that
His promise ___ he would marry her when he came back turned out to be a lie, ___ left the girl heart-broken.
#78093
A
which; what
B
that; which
C
what; which
D
which ; that
Modern science has given clear evidence ______ smoking can lead to many diseases.
#78419
A
what
B
which
C
that
D
where