本题主要考查英译汉．Why为什么，are是，you你，so如此，tried疲劳的．结合整句与中文的表达习惯作答．
故答案为：你为什么如此疲劳？
why is she so tired怎么回答
She is feeling tired because she has been working/studying hard all day/week. 或者 She is feeling tired because she didn't get enough sleep last night. 等等。可以根据具体情况来回答。
why is she so tired怎么回答
用why问，用because来回答，理由很多，譬如，Because she keeps playing football for an hour.