问题补充：
The earth is 49 times the moon.
A. as bigger as
B. so big as
C. the size of
D. of the size of
答案：
A. as bigger as
B. so big as
(答案→)C. the size of
D. of the size of
解析：倍数有三种表达法：⑴A is three times bigger than B⑵A is three times the size of B⑶A is three times as big as B。这符合第二种。
