It is already well understood___________ causes the global warming.
#70555
A
what
B
when
C
how
D
that
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(2013·芜湖三校二模)I really can't think of ________ told me you were not coming back till tomorrow.
#67258
A
it was who that
B
who was it that
C
that who was it
D
who it was that
People have heard what the President has said; they are waiting to see ________ he will do.
#73930
A
how
B
what
C
when
D
that