335. I (we) should

334. If I (we,you,he,she,it,they)+had+过去分词

333. 主句的动词形式

332. 条件从句的动词形式

331. ②用法：

a) If I had more time, I should study German.(fact:I have no more time, so I shall not study German. )

b) If she were not so busy, she would attend the meeting this afternoon.(fact:she is very busy, so she will not attend the meeting this afternoon.)

c) If they didn’t take physical exercises every day, they wouldn’t be so healthy.(fact: they take physical exercises every day, so they are very healthy.)

a) 表示与过去誓死相反的情况

d) ①形式；

330. 所有人称+might(could)+动词原形

329. they,it ) would

328. You (he,she , +动词原形或：

327. I (we) should

326. If I (we,you,he,she,it,they)+行为动词的过去式(be的过去式一般用were)