说明

现在完成时强调「与现在有关」，常配 for / since / already / yet / ever；一般过去时强调「过去某个时间点结束」，必须配明确过去时间（in 2010、yesterday）。两者不能和具体过去时间连用完成时。

同类条目

• 主谓一致：就近原则 —— Either you or he is right.
• 定语从句：that 与 which —— The book that/which I bought is good.
• 虚拟语气：if 条件句 —— If I were you, I would take it.
• 非谓语：doing 与 to do —— I enjoy reading. / I want to go.
• 倒装：否定词提前 —— Never have I seen such a thing.
• 比较级：as ... as 与 than —— He is as tall as I am. / He is taller than I am.
• 情态动词表推测 —— It must be true. / It can't be true.
• 被动语态的基本结构 —— The letter was written by Tom.