问题补充：
At a rough estimate, our new library is the old one.
A. three times the size as
B. the size three times of
C. three times as the size of
D. three times the size of
答案：
A. three times the size as
B. the size three times of
C. three times as the size of
(答案→)D. three times the size of
解析：考查倍数。本题考查倍数问题，这里考查倍数 + the + 名词 + of结构。句意：据初步估计，我们的新图书馆是旧图书馆的3倍大。故D正确。
