Question

--- Did you and your friends ride your bicycles to the beach yesterday afternoon?

--- Yeah. ________ we had!

1. A.
   How a fun
2. B.
   What fun
3. C.
   What a fun
4. D.
   How fun

Answer 1

B
考查名词单复数及感叹句用法。感叹句用法区别：What+a /an+adj.+n. (可数名词单数) +主语+谓语！What+ (adj.) +n. (可数名词复数) ／ (不可数名词) +主语+谓语！How+adj.+a /an+n. (可数名词单数) +主语+谓语！How+adj.+n. (可数名词复数) ／ (不可数名词) +主语+谓语！How+adj. /adv.+主语+谓语！
又因为fun是不可数名词，故B项正确。