你好,同學 正確答案： What are you doing on such a rainy day? 解析：在具體的某一天,或者有形容詞修飾的某一天前用介詞on 或：What are you doing when it rains? 天下雨時,你在做什么?希望能幫到你,祝更上一層...What are you doing 后有三個空What are you doing when it rains? 天下雨時，你在做什么？如果有四個空呢？麻煩您給我翻譯一下。謝謝您了What are you doing on a rainy day? 在一個下雨天你在做什么？