All you ever do is criticize！你就知道批评！这句话看似简单，其实包含了不少值得分析的语法点。语法点1. ——主语部分：all you ever do，包含定语从句—you ever do所有你曾经做过的事情，all是先行词，在定语从句中作do的宾语，因为作宾语，所以关系词that可以省略。所以，主语部分，完整的形式应该是：all that you ever do 拓展阅读：定语从句中，只用that不用which的4种情况： 1. 当先行词中有人又有物时:Do you know the things and persons that they are talking about?你了解他们在讨论的人和事吗？ 2. 当先行词为不定代词all, the one, much, few, little, no, some, any, everything, nothing, none等时：This is all that I want from the school.这是所有我想从学校中获得的东西。The thief handed everything that he had stolen to the police.这个小偷把他偷的每一样东西都交给了警察。 3. 当先行词被the only, the very, the right, last, just, all, few, little和最高级，序数词等绝对性形容词修饰时：This is the first film that I have seen since I moved here.这是我搬到这里看的第一部电影。This is the very book that I am looking for these days.这正是我最近几天在找的那本书。The TV tower is the highest building that has been built in this city.这座电视塔是这座城市最高的建筑。The first lesson that I learned will never be forgotten.我学到第一课永远难忘。 4. 用于which或who开头的特殊疑问句Which is the house that was burnt yesterday?昨天被烧毁的房子是哪个？Who is the girl that is dancing with Tom?和汤姆在跳舞的那个女孩是谁？ 语法点2. —— 不定式作表语，主语部分含有实义动词do的某种形式，比如，do，does，did等，可以省略不定式to do中的to，即：（to) do。也可以这样说，不定式包含两种形式：1. to do（非谓语动词）2. do（省略to，也是非谓语动词）题主给出的例句:【All you ever do】is criticize.主语部分all you ever do含有do，因此，表语部分的criticize是省略了to的不定式。完整的句子形式应该是：All (that) you ever do is （to） criticize. 这种省略现象，通常称为前有do后无to。 更多类似例句：1. What I want to do is stay at home. 我就想待在家里。 2. All we need to do is live each day with hope. 我们需要做的就是带着希望过好每一天。 3. The only thing I can do now is stick to the goal. 我现在能做的唯一一件事就是坚持这个目标。 4. What the government will do next year is protect the ocean. 政府下一年要做的事是保护海洋。
