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：the blue whale特指“蓝鲸”这类动物；第二个空表泛指，a 9－story building意为“一座9层高的大楼”。