虚拟语气
The Subjunctive Mood
英语动词有三种语气：陈说语气，祈使语气，虚拟语气。
一、 陈说语气
用来陈说一个事实，或提出一个看法。有必定，否定，疑问或感叹等形式。
There are two sides to every question.They didn’t watch fireworks yesterday evening.What can I do for you ?

Shall I turn on the radio?How disappointed Tom was !What lovely flowers those are!