八年级英语上册语法知识点:情态动词/特殊疑问句的变换情态动词can(能,会), may(可以,可能,也许), must(必须,一定,应该) have to(必须,不得不)1. 肯定句结构:主语+can/may/must+动词原形+其它,例如:I must go now.2. 否定句结构: 在can/may/must后加not,例如:You mustn’t talk aloud in the library.3. 一般疑问句结构: 把can/may/must提在主语前,例如:Must you go now? (Yes, I must. No, I needn’t.)May I open the window? (Yes, you may. No, you needn’t.)had better用法had better+动词原形表示“最好做……”,变否定句时在had better后加not。例如:You had better catch a bus.You’d better not catch a bus. (You had= You’d ) 特殊疑问句的变换对划线部分提问时,将划线部分去掉,剩下部分变一般疑问句语序。(对主语提问例外)例如:My name isLily. What’s your name?The river is500 kilometres. Hong long is the river?