问题补充：
Paper bags produced every year are the world’s production of vehicles.
A. three times the weight of
B. three times weight of
C. as three times heavy as
D. three times as heavier as
答案：
(答案→)A. three times the weight of
B. three times weight of
C. as three times heavy as
D. three times as heavier as
解析：本题考查倍数的表达方式。句意：每年生产的纸的重量是全世界生产车辆重量的三倍。英语倍数的表达法有：
（1）……倍数+形容词（或副词）的比较级+than
（2）……倍数+as+形容词（或 much）或副词+as
（3）……倍数+the size（length，height…）of
