虛擬語氣表示說話人的愿望、假設、猜測或建議,而不表示客觀存在的事實。虛擬語氣通過謂語動詞的特殊形式來表示。下面分別介紹虛擬語氣在各種句式中的用法。
1.虛擬語氣用于條件狀語從句
注意:主句中的should通常用于第一人稱,would可用于任何人稱,同時也可根據意思用情態動詞could,might等代替should,would。
1)表示與現在事實相反:
If I were you,I should stay at home.
If the peasants could farm the land themselves,food production would be much higher.
If fewer cash crops were grown,more food could be produced and there would be less or no starvation.
2)表示與過去事實相反:
If you had come yesterday,you would have met him.
If the hurricane had happened during the daytime,there would have been many deaths.
3)表示與將來事實相反:If you came tomorrow,we would have the meeting.
If it were to/should rain tomorrow,the meeting would be put off.
If it should rain,the crops would be saved.
4)當條件狀語從句表示的行為和主句表示的行為所發生的時間不一致時,動詞的形式要根據它所表示的時間來調整。例如:If you had followed the doctor's advice,you would be quite all right now.(從句說的是過去,主句指的是現在。)
5)以上句型可以轉換成下列形式:①從句省略if,用倒裝句式"were,had,should 主語"。例如:Were I in school again,I would work harder. Had you been here earlier,you would have seen him. Should there be a meeting tomorrow,I would come.②用介詞短語代替條件狀語從句。例如:Without air, there would be no living things. I would not have succeeded but for your help.
 

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