To do smth is necessary/impossible (the adjective)
was a mistake/a problem (the noun)
will be to do smth (the infinitive)
E.g.: To err is human. (in older use)
To visit her is always a pleasure.
To make mistakes is easy.
Where to start was a problem.
To break your promise would be wrong.
1)In older English, an infinitive preceding the predicate could easily be the subject of a sentence. In modern English, this is unusual in an informal style. Widely used are sentences with “it” as a formal subject and the notional subject expressed by the infinitive following the predicate. It’s nice to see you again. (Pattern 2)
2)If there are two or more homogeneous infinitive subjects in a sentence, all of them keep the particle to: It was awfully difficult to do or even to say nothing at all.
3)The predicate of the subject expressed by the infinitive always takes the form of the 3d person singular: Not to go backwas awful.
4)The predicate of the subject expressed by the infinitive is usually a compound nominal predicate with the link verb to be, although other link verbs may also occur: To lean out of the windowis dangerous. To save money nowseems impossible. To compromiseappears advisable. Sometimes sentences with the subject expressed by the infinitive have other types of predicates:To wait for people who were latemade him angry.(the simple verbal predicate)
Exercise 5. Complete each statement and comment on the function of the infinitive:
Pattern: To succeed at one’s job requires hard work.
1.To find a job … . 2. To lose one’s job … . 3. To raise children … . 4. To have a lot of friends … . 5. To travel … . 6. To meet new people … . 7. To do the same thing every day …. 8. To tell her the truth. … . 9. To think so. . . . 10. To help them. . . .
Exercise 6. Complete the following using the infinitive phrases from the list:
To forget the past, to be humming a tune, to say a thing to a child, to have gone out that rainy day, to know the map well
1. . . . means to be able to show any country or town on it. 2. . . . would have been the death of me. 3. . . . is a usual thing for her. 4. . . . would be ridiculous. 5. . . was impossible.
It is necessary (the adjective) to do smth
was important/interesting/easy /difficult/nice to be done
will be a pleasure (the noun) to be doing
E.g.: It’s easy to make mistakes.
Itwas niceto be speaking English again.
It is a great pleasure to see you.
It was very nice to be talked to like that.
Exercise 7. Complete each statement and comment on the function of the infinitive:
A. Pattern: It’s illegal to sell drugs.
1.It’s expensive… 2. It’s important … 3. It’s easy … 4. It’s dangerous… 5. It isn’t healthy … 6. It isn’t polite …
B. Pattern: It’s impolite to be perfect.
1…. To trust other people. 2. … to work hard. 3. … to fall in love. 4. … to get married. 5. … to make a mistake. 6. … to be lonely. 7. … to help other people.
C. Pattern: It takes me an hour to get dressed in the morning.
1. … to get to class. 2. … to get ready in the morning. 3. … to come to the United States. 4. … to do my homework. 5. … to learn English.
D. Pattern: It cost me $ 75.00 to buy this book.
1. … to come to the United States. 2. … to eat lunch in the cafeteria. 3. … to take a taxi downtown. 4. … to send a registered letter to my country. 5. … to make a long-distance call to my hometown.