The biggest whale is blue whale which grows to be about 29 meters long—the height of 9s

问题补充：

The biggest whale is blue whale，which grows to be about 29 meters long—the height of 9story building.

A. the；the

B. a；a

C. a；the

D. the；a

答案：

A. the；the

B. a；a

C. a；the

(答案→)D. the；a

解析：句意：最大的鲸鱼是蓝鲸，它可以长到大约29米长——一座9层楼的高度。前一空格处是“the＋单数可数名词”表类指；后一个空表示泛指。

答案D