【小编寄语】今天查字典英语网小编教给同学们的是动词不定式作主语的用法，一起来学习下吧!祝同学们学习进步!
一、不定式等非谓语形式作主语时，谓语动词一路走来都是单数身份;不少作主语的不定式与动名词在意义上相同。如：
To see is to believe. = Seeing is believing. 眼见为实。
二、口语中，当作主语的不定式过长时，it不惜屈居有名无实的形式主语，常为平衡关系而挺身而出、替主出征，"真主角"反无官一身轻，悠哉断后。如：
To learn a foreign language well is not easy.→ It's not easy to learn a foreign language well. 要把一门外语学好不容易。
To play football is very interesting. → It's very interesting to play football. 踢足球很有趣。
留言提醒：在实际操作中，不定式(短语)还有权"招聘"一个逻辑主语，并由of / for出面"料理"--It's + adj. + for / of sb. + to do sth.，下例中的"for me"即是：
It's hard for me to finish the task in such a short time. 对我而言，要在如此短的时间里完成任务是困难的。
聘of还是for?点击作表语的形容词属性可知：若形容词描述的是人的特征与品行，能修饰人(像kind， nice， good， clever， right， polite， careless等)，则"of适宜";如果形容的是事物的特点或外观等(如easy，hard / difficult， safe， interesting， important，necessary之类)，则"for主动上"!下例"正误"可略见一斑：
出席这个会议对你来说很重要。
[误] It's very important of you to attend the meeting.
[正] It's very important for you to attend the meeting.
留言提醒：检验形容词描绘的是不是人的特征与品行、能否修饰人--"sb. be adj."可助上一臂之力。
三、一个都不能少：还有几种耳熟能详的"不定式作主语"句式。如：
1. It takes / took / will take (sb.) some time to do sth.如：
It takes (us) hours to do our homework every day. 我们每天要花上数小时做家庭作业。
2. It's + n. + to do sth.如：
It's a mistake for us not to help him. 我们不帮他是个错误。
留言提醒：要对不定式否定，暗号照旧--not在不定式前面加!
3. It cost / costs sb. some time / money to do sth. 如：
It cost me ten yuan to buy this bag. 我花了十元钱买这个书包。
四、时代流行风--主语也能由疑问词how / what / when / where / which等携手与不定式"联袂出演"。如：
Where to put the bikes is being discussed. 把自行车放哪儿正在讨论当中。
When and where to have the meeting hasn't been known. 什么时候、什么地方开会还是未知数。