你好,同学 正确答案： What are you doing on such a rainy day? 解析：在具体的某一天,或者有形容词修饰的某一天前用介词on 或：What are you doing when it rains? 天下雨时,你在做什么?希望能帮到你,祝更上一层...What are you doing 后有三个空What are you doing when it rains? 天下雨时，你在做什么？如果有四个空呢？麻烦您给我翻译一下。谢谢您了What are you doing on a rainy day? 在一个下雨天你在做什么？