Question

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

Answer 1

C

本題考查定語從句。Which引導非限制性定語從句，代指前面的一句話。句意：他們把太多的二氧化碳排到大氣中，阻止了熱從地球逃逸到太空中。