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
Many countries are now setting up national parks animals and plants can be protected.
#76501
A
when
B
which
C
whose
D
where
The factory produces two million pairs of shoes every year, half _______ are sold abroad.
#77856
A
of which
B
which of
C
of them
D
of that
It was in the Lake District _______ the poet William Wordsworth spent much of his lifetime.
#78505
A
how
B
that
C
which
D
where
________ is often the case with elder people, my grandma talked about my new hairstyle for at least 50 minutes nonstop.
#76595
A
That
B
Which
C
As
D
It
She'll never forget her stay there ________ she found her son who had gone missing two years before.
#75565
A
that
B
which
C
where
D
when