1) When an adjective follows a linking verb with a personal subject (rather than ‘It…’) we can put a number of things after the adjective.
ç That-clause (to talk about someone’s feeling or opinion, or about how sure we are of something)
afraid, alarmed, amazed, angry, annoyed, ashamed, astonished, aware, concerned, delighted, disappointed, glad, (un)happy, pleased, shocked, sorry, upset, worried, certain, confident, positive, sure (with the exception of aware and confident these can also be followed by a to-infinitive)
- He became worried (that) she might leap out from behind a door.
- She felt certain (that) she’d seen him before.
(un)able, careful, crazy, curious, difficult, easy, free, good, hard, impossible, inclined, nice, prepared, ready, welcome,willing.
- You’re free to leave at any time you want.
- They’re very easy to please.
busy, worth (these can’t be followed by a that-clause or to-infinitive)
Example: He was busy doing his homework.
NOTE: Most of the adjectives listed as being followed by a to-infinitive can’t be followed by a that-clause. However, for the adjectives underline above we can use adjective + to-infinitive + that-clause.
- She was ready to admit (that) I was right.
- They were prepared to accept that my idea was a good one.
2) Sometimes we can use adjective + preposition + ing-form oradjective + to-infinitive with little difference in meaning.
- I’m sorry to disturb you. (= I’m disturbing you now)
- I’m sorry for disturbing you. (= I disturbed you earlier)
3) It + linking verb + adjective
We can often avoid beginning a sentence with a that-clause or a to-infinitive, by using ‘It…’
- It became clear that I wasn’t welcome. (rather than That I wasn’t welcome was clear.)
- It is essential to get there early. (rather than To get there early is essential.)
NOTE 1: We can put of + subject or for + subject between the adjective and a to-infinitive.
For adjectives which take of + subject include careless, greedy, kind, nice, silly, wrong, generous…
For adjectives which take for + subject include easy, essential, hard, important, impossible, necessary, unacceptable, vital, difficult…
- It was generous of her to take on the job. (or She was generous to take on the job.)
- It seemed difficult for him to walk.
NOTE 2: We can also use it + adjective after verbs such as believe, consider, feel, find, think before a that-clause or to-infinitive.
- I thought it dreadful that Liz was asked to resign.
- They consider it wrong to smoke in public places.