问题:
It’s the gases ___ natural gas and the burning of coal give off ____ add to the overheating of the earth.
A.that; what
B.that; that
C.which; which
D.that; which
It’s the gases ___ natural gas and the burning of coal give off ____ add to the overheating of the earth.
A.that; what | B.that; that | C.which; which | D.that; which |
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