问题
选择题
They are putting too much carbon dioxide into the atmosphere, ______ prevents heat from escaping from the earth into space.
A．what
B．that
C．which
D．who
答案
答案：C
本题考查定语从句。Which引导非限制性定语从句，代指前面的一句话。句意：他们把太多的二氧化碳排到大气中，阻止了热从地球逃逸到太空中。