The functions In the sentence the infinitive is used: As a subject. If the subject of the sentence is an infinitive phrase it is often placed after the predicate and the sentence begins with the introductory it. e.g. To know him is to trust him. It wasn’t safe to cross the bridge at night.
The infinitive may be preceded by the pronouns what, whom, whose, which, by the adverbs where, when, how, why and by the conjunction whether and if. The infinitive phrases of this kind are most frequently used in the function of an object. e.g. I knew where to look for her. I don’t know how to do it. We don’t know what to do with these people.
1. After verbs to see, to hear, to feel, to observe, to notice. She saw Mary cry. I heard her call my name. to V 2. After verbs to wish, to want, to desire, to like, to dislike, to hate, to intend, should, would like. She wanted them to read this book. I’d you to come to our party. to V 3. After verbs to consider, to believe, to think, to find, to expect, to suppose. We considered him to be the best pupil of our form. We expect the delegation to come at 5. to V 4. After verbs to ask, to order, to allow, to advise, to recommend. We asked Josh to work. The office ordered the soldiets to stand still. to V
Complex Subject noun pronoun to V The Subjective Infinitive Complex consists of a noun in the Common Case or a personal pronoun in the Nominative Case and the infinitive. The nominal part of the complex may denote both the subject and the object of the action expressed by the infinitive.
1. After verbs to see, to hear, to feel, to observe, to notice. Mary was seen to cry. She was heard to call my name. Passive 2. After verbs to consider, to believe, to think, to find, to expect, to suppose. He is considered to be the best pupil of the form. The delegation is expected to come at 5. Passive 3. After verbs to say, to report. He is said to be a bad man. The delegation is reported to be late. Passive 4. After verbs to ask, to order, to allow, to advise, to recommend, to let, to make. They were ordered to stand still. He was made to leave the hall. The children were let to go to the cinema. Passive
5. After verbs to seem, to appear, to happen, to chance, to turn out, to prove. He seemed to be thinking about something. I happened to see her in the street. They turned out to be good friends. Active 6. After word combinations to be certain, to be likely, to be unlikely, to be sure. They are likely to come. He is unlikely to win this game. He is sure to know something. Active
In the sentence the Prepositional Infinitive Complex may be used in the functions of: subject e.g. For me to see you is the happiest minute in my life. It’s dangerous for us to be going out in this car. predicative e.g. That’s for you to think on. object e.g. He waited for her to speak.