当主语在谓语前出现时叫顺序(the natural order)。在某些情况下，我们可以把谓语成分放在主语前面，这种词序叫做倒装( the inverted order)。
倒装分两种：配合语法条例的倒装，叫“grammatical inversion”;配合强调语势的叫“emphatic inversion”。
语法上的倒装句是强制性的，包括下列 7 种：
⒈疑问句，如：
● Can you do it?
● How old are you?
● When did you know him?
● Why did you elect him as captain?
● Which of these apples do you prefer?