7.14 不定式的时态和语态 时态\语态 主动 被动一般式 to do to be done进行式 to be doing 完成式 to have done to have been done完成进行式 to have been doing 1) 现在时：一般现在时表示的动词，有时与谓语动词…...

11.27 时态一致 1) 如果从句所叙述的为真理或不变的事实，则永远用现在时。 At that time, people did not know that the earth moves. He told me last week that he is eighteen. 2) 宾语从句中的助动词ought, need, must, dare 时态是不变的。 H…...

11.22 一般现在时代替将来时 时间状语从句，条件句中，从句用一般现在时代替将来时When, while, before, after, till, once, as soon as, so long as, by the time, if, in case (that), unless, even if, whether, the moment, the minute, the day,…...

11.17 将来完成时 1) 构成will / be going to do sth. 2) 概念 a. 状态完成：表示某事继续到将来某一时为止一直有的状态。 b. 动作完成：表示将来某一时或另一个将来的动作之前，已经完成的动作或一获得的经验。 They will have been married f…...

11.11 用于现在完成时的句型 1）It is the first / second time…. that…结构中的从句部分，用现在完成时。 It is the first time that I have visited the city. It was the third time that the boy had been late.2）This is the… that…结构，…...

11.6 be to和be going to be to 表示客观安排或受人指示而做某事。 be going to 表示主观的打算或计划。 I am to play football tomorrow afternoon. (客观安排) I'm going to play football tomorrow afternoon. (主观安排) ...