it is to jump into a river to swim on such a hot day.A. What a fun B. What fun C. How a f

问题补充：

it is to jump into a river to swim on such a hot day.

A. What a fun

B. What fun

C. How a funny

D. How a fun

答案：

A. What a fun

(答案→)B. What fun

C. How a funny

D. How a fun

解析：本题是感叹句，what后跟名词，how后跟形容词或副词，fun是不可数名词，无需加冠词，故本题选B。