if的虛擬語氣用法 if的虛擬語氣用法是怎樣

1、提出將來會發生的事：主句：主語＋would/should/might/could＋動詞原形；從句：should＋動詞原形/were to＋動詞原形。例句：If he should go to Harvard University, he would make full use of his time.如果他要上哈佛大學的話，他就會充分利用他的時間了。

2、提出現在的條件：主句：主語＋would/should/might/could＋動詞原形；從句：動詞過去式。例句：If he studied at this school, he would know the enviornment around the school very much.如果他在這所學校學習的話，他會很瞭解周邊環境。

3、提出過去的未發生的條件：主句：主語＋would/should/might/could have＋動詞過去分詞；從句：had＋動詞過去分詞。例句： If I had read the book, I would have told you about it.我如果看過本書，我會把內容告訴你了。