Paper produced every year is _______ the world's production of vehicles.
A.the three times weight of B.three times the weight of
C.as three times heavy as D.three times as heavier as
昨日习题答案：
标准答案是：A
本题解析:同位语从句that we'll never know what a UFO is — not ever作a feeling的同位语,解释a feeling的具体内容.that连接同位语从句时,只起连接作用,不作从句的任何成分.