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
推荐题目
Bungee jumping is a thrilling and adventurous sport, very popular among the young adults, ________ courage matters more than strength.
#78271
A
whose
B
that
C
of which
D
where
I wish to thank Professor Smith, without _______help I would never have got this far.
#77989
A
who
B
whose
C
whom
D
which
Beijing was attacked by such a terrible sandstorm __________few citizens has ever experienced before.
#77869
A
where
B
as
C
when
D
which