三、 不定式作表语
(一)一种情况为主语是不定式(表示条件)，表语也是不定式(表示结果)
To see is to believe/ To work means to earn a living.
(二)另一种情况主语是以aim, duty, hope, idea, happiness, job, plan, problem, purpose, thing, wish等为中心的名词，或以what引导的名词性从句，不定式表语对主语起补充说明作用
- The function of Louis Sullivan's architecture was providing ［A］ large uninterrupted floor areas ［B］ and to allow ample light ［C］ into the interior ［D］ .
- The most important ［A］ thing is negociate ［B］ with them about ［C］ the future of ［D］ the plant.
His wish is to buy a luxurious car in the near future. / The boss's plan is to start building the skycraper immediately. / What I want to say is to get rid of the plan forever.
