问题补充：
At a rough estimate, Nigeria is Great Britain.
A. twice big as
B. as twice big as
C. three times the size as
D. three times the size of
答案：
A. twice big as
B. as twice big as
C. three times the size as
(答案→)D. three times the size of
解析：句意：粗略估计，尼日利亚是大不列颠的三倍大。我们要表达甲是乙的几倍时，通常用下面三个句型来表示： 1. “A+倍数+形容词或副词的比较级+than+B”，表示“A比B大（长、高、宽等）多少倍”。如： This rope is twice longer than that one. 这根绳子是那根绳子的两倍长（比那根绳子长一倍）。The car runs twice faster than that truck. 这辆小车的速度比那辆卡车快一倍（是那辆卡车的两倍）。2.“A+倍数+as+形容词或副词的原级+as+B”，表示“A正好是B的多少倍”。如： Asia is four times as large as Europe. 亚洲的面积是欧洲的四倍。The plane flew ten times as high as the kite. 那架飞机的飞行高度是那只风筝的十倍。3. “A+倍数+the size/height/length/width, etc+of+B”，表示“A正好是B的多少倍”。如： This street is four times the length of that one. 这条街是那条街的四倍长。This hill is four times the height of that small one. 这座山的高度是那座小山的四倍，由题干可知选D正确。
考点: 考查形容词倍数的用法。
