一、语法一致的原则
语法一致是指主语为单数形式，谓语也用单数形式；主语为复数形式，谓语也用复数形式。
1、动词不定式或动词–ing形式作主语
动词不定式或动词–ing形式作主语时，谓语动词用单数。
To see is to believe.
眼见为实。
Asking costs nothing.
多问不吃亏。
2、从句作主语
名词性从句作主语时，谓语动词一般用单数形式。
That they will win is certain.
他们一定会赢是确信无疑的。
When they could finish the task is not known yet.
他们何时能完成任务还未知。
Whoever wants to join in the competition is asked to sign his / her name here.
要参加比赛的人请在这里签名。
