问题补充：
--- great fun it was to see the basketball final yesterday! What about you?
--- What a pity! I had a lot of work to do yesterday.
A What a B How a C How D What
答案：
解析：what引导的感叹句的结构为：What +形容词+n【U】或n【C】复数形式+主谓！，或What a 或an+adj+n【C】单数形式+主谓！而how +adj或adv+主+谓！本句符合What +adj+n【U】+主谓！fun为不可数名词。故选答案为D
