高二語法專題二：虛擬語氣
英語語法有成套的系統，但還是需要同學們利用零碎的時間進行逐項突破。虛擬語氣：表示假設的情況與事實相反，或發生的可能性不大。卓越教育小編整理了相關資料，以供參考：
虛擬語氣的常見用法和常見場景：
1. if 引導的虛擬條件句
條件從句
條件從句的謂語形式
主句的謂語形式
與過去事實相反
had +過去分詞
should/would/could/might+hav done
與現在事實相反
were; did
should/would/could/might+動詞原形
與將來事實相反
did; should do; were to do
should/would/could/might+動詞原形
2.這些動詞後面接的賓語從句：表示建議(suggest, advice, propose, recommend) ，要求(demand, request, require, insist), 命令(order, command)等，從句謂語用：should + 動詞原形, should 可省略。 (注意：insist 表示“堅稱，堅持說”，suggest 表示“表明、暗示”時, 用陳述語氣，表示事實。)
The teacher suggested that we (should) clean the blackboard after class.
The smile on his face suggested that he was happy to have given his life for his country.
3. wish;as if; as thought 及if only(若是……那該多好啊)引導的從句中有三種情況：
1) 與現在事實相反：用過去式
如：I wish I were 30 years younger. 我但願自己能年輕三十歲。
2) 與過去事實相反：用過去完成式
如：He wished he hadn't done it. 他想要是他沒這樣做該多好。
3) 與將來事實相反：用情態動詞(would / could) + do
如：I wish she would be on my side. 我希望她能站在我一邊。
4. 在句型 “It is important (necessary, strange, natural) that .... ” that 後面從句中的謂語動詞用: should + 動詞原形(should不能省略)。
如：It is important that we should form a good habit.
在句型“It’s (high/right) time that…”中，謂語動詞用：過去時或should + 動詞原形(should不能省略)。
如：It is about time that we started\should start a trip.
5. 在would (had) rather(寧願) 引導的賓語從句中, 當從句表示現在或將來的時間時,謂語動詞要用一般過去時; 表示過去時間時,謂語動詞要用過去完成時。
如：Mary wouldrather that she had not gone to the ball 10 years ago.
6. 一些介詞短語, 如:but for(要不是), without, otherwise(否則), in that case(如果是那樣的話), 表示含蓄的條件, 這時主句要用虛擬語氣。
Without your help, we would not have made such rapid progress.
原作者： 卓越教育小編