虛擬語氣的一些其他用法
1.在表示愿望、建議、要求、命令等含義的動詞及其派生的同根名詞后面的主語從句、表語從句及同位語從句中的謂語一般用虛擬語氣，即“should +動詞原形”或只用動詞原形。這類從句常見的動詞有：demand, desire, request, require, propose, suggest, recommend, move (提議), order, command, insist等。如：
e.g. It is required that the equipment should be tested again before it is actually put into operation.
這臺設備在實際投入運行前要求再測試。
e.g. The experts recommended that highways be provided with sensors buried beneath them to emit signals to the car.
專家們建議在公路路面下埋置傳感器使之能向汽車發(fā)出信號。
e.g. We all insist that we not rest until we finish the work.
大家都堅決要求不完工就不休息。
2.某些形容詞后面的主語從句的謂語用虛擬語氣
在It is necessary (important, imperative必須的，essential, advisable可取的，better)等句型中的主語從句中，謂語一般用“should +動詞原形”或只用動詞原形。如：
e.g. It is imperative that Franck do away with his bad habit.
弗蘭克改掉他的壞習慣是絕對必要的。
e.g. It is essential that men in space should take their own air with them in order to breathe.
太空人為了呼吸，自備氧氣是必不可少的。
3.在wish后的賓語從句中，謂語用虛擬語氣。
動詞wish后的賓語從句，表示未實現的主觀愿望。這時，賓語從句的謂語動詞用虛擬語氣。如：I wish I could afford a new car. 我要是能買得起一輛嶄新的汽車就好了。
具體形式及用法如下表：
賓語從句謂語形式(例詞know)
用法
過去式knew
表示現在未實現的愿望
過去完成式had known
表示過去未實現的愿望
過去將來式would know
表示將來不大可能實現的愿望
謂語動詞be的過去時為were，適用于一切人稱。例如：
e.g. I wish my mother were in good health.我真希望我母親現在的身體健康。
4.在以as if, as though (好像，似乎)引出的與事實不符的狀語從句中，謂語用虛擬語氣，其形式一般用動詞的過去式表示對現在情況的推測。用過去完成式表示對過去情況的推測。如：
e.g. The moon shines brightly, as if it gave off light by itself.
月亮照得很明亮，仿佛它本身發(fā)光一樣。
e.g. I was horrified at his appearance. He looked as though he hadn’t slept for weeks.
他的外表嚇了我一跳，看上去似乎好幾個星期沒睡覺。
注：
在由as if, as though引導的從句中通常用虛擬語氣，但如果從句中所傳述的情況實現的可能性較大，則用陳述語氣。如：
e.g. It looks as if it is going to rain.
天似乎要下雨了。
5. 用should (would), could, might + 動詞原形的形式表示委婉的虛擬語氣
e.g. We’ll have soup to start with. What would you like after that?
我們首先上湯，接著你們喜歡上什么菜?
e.g. The expert explains that the car’s computer might reduce the car’s speed to get it out of danger.
專家解釋說汽車上的計算機可以使減速從而避免危險。
6.在“it is (high, about) time+從句”中，表示早該做而沒有做的事，含建議的意味，其從句謂語動詞用過去式。例如：
Ø It’s (high) time (that) we left now.
現在我們該走了。
It’s (about) time (that) the children went to bed.
孩子們該上床睡覺了。
Ø 課堂練習：
1) We require that the leader ____ us immediately of any change in plans.
A inform B informs C informed D has informed
2) ____ before we depart the day after tomorrow, we should have a wonderful dinner party.
A Had they arrived B Would they arrive C Were they arriving D Were they to arrive
3) ____ for my illness I would have lent him a hand.
A Not being B Had it not been C Without being D Not having been
1.在表示愿望、建議、要求、命令等含義的動詞及其派生的同根名詞后面的主語從句、表語從句及同位語從句中的謂語一般用虛擬語氣，即“should +動詞原形”或只用動詞原形。這類從句常見的動詞有：demand, desire, request, require, propose, suggest, recommend, move (提議), order, command, insist等。如：
e.g. It is required that the equipment should be tested again before it is actually put into operation.
這臺設備在實際投入運行前要求再測試。
e.g. The experts recommended that highways be provided with sensors buried beneath them to emit signals to the car.
專家們建議在公路路面下埋置傳感器使之能向汽車發(fā)出信號。
e.g. We all insist that we not rest until we finish the work.
大家都堅決要求不完工就不休息。
2.某些形容詞后面的主語從句的謂語用虛擬語氣
在It is necessary (important, imperative必須的，essential, advisable可取的，better)等句型中的主語從句中，謂語一般用“should +動詞原形”或只用動詞原形。如：
e.g. It is imperative that Franck do away with his bad habit.
弗蘭克改掉他的壞習慣是絕對必要的。
e.g. It is essential that men in space should take their own air with them in order to breathe.
太空人為了呼吸，自備氧氣是必不可少的。
3.在wish后的賓語從句中，謂語用虛擬語氣。
動詞wish后的賓語從句，表示未實現的主觀愿望。這時，賓語從句的謂語動詞用虛擬語氣。如：I wish I could afford a new car. 我要是能買得起一輛嶄新的汽車就好了。
具體形式及用法如下表：
賓語從句謂語形式(例詞know)
用法
過去式knew
表示現在未實現的愿望
過去完成式had known
表示過去未實現的愿望
過去將來式would know
表示將來不大可能實現的愿望
謂語動詞be的過去時為were，適用于一切人稱。例如：
e.g. I wish my mother were in good health.我真希望我母親現在的身體健康。
4.在以as if, as though (好像，似乎)引出的與事實不符的狀語從句中，謂語用虛擬語氣，其形式一般用動詞的過去式表示對現在情況的推測。用過去完成式表示對過去情況的推測。如：
e.g. The moon shines brightly, as if it gave off light by itself.
月亮照得很明亮，仿佛它本身發(fā)光一樣。
e.g. I was horrified at his appearance. He looked as though he hadn’t slept for weeks.
他的外表嚇了我一跳，看上去似乎好幾個星期沒睡覺。
注：
在由as if, as though引導的從句中通常用虛擬語氣，但如果從句中所傳述的情況實現的可能性較大，則用陳述語氣。如：
e.g. It looks as if it is going to rain.
天似乎要下雨了。
5. 用should (would), could, might + 動詞原形的形式表示委婉的虛擬語氣
e.g. We’ll have soup to start with. What would you like after that?
我們首先上湯，接著你們喜歡上什么菜?
e.g. The expert explains that the car’s computer might reduce the car’s speed to get it out of danger.
專家解釋說汽車上的計算機可以使減速從而避免危險。
6.在“it is (high, about) time+從句”中，表示早該做而沒有做的事，含建議的意味，其從句謂語動詞用過去式。例如：
Ø It’s (high) time (that) we left now.
現在我們該走了。
It’s (about) time (that) the children went to bed.
孩子們該上床睡覺了。
Ø 課堂練習：
1) We require that the leader ____ us immediately of any change in plans.
A inform B informs C informed D has informed
2) ____ before we depart the day after tomorrow, we should have a wonderful dinner party.
A Had they arrived B Would they arrive C Were they arriving D Were they to arrive
3) ____ for my illness I would have lent him a hand.
A Not being B Had it not been C Without being D Not having been