G. Difficult to understand etc. (e.g. Jim doesn’t speak very clearly. (a) It is difficult to understand him. (b) He is difficult to understand. (not He is difficult to understand him)
a. can use same structure with: easy, good, hard, interesting, impossible, exciting, dangerous, safe, expensive, cheap, nice. (e.g. Do you think it is safe (for us) to drink? or Do you think this water is safe (for us) to drink? (not to drink it))
b. can also use this structure with adjective + noun. (e.g. This is a difficult question (for me) to answer. (not to answer it)
G1. (It’s) nice of (you) to ~
a. can say ‘It’s nice of somebody to do something’ (e.g. It was nice of you to take me to the airport. Thank you very much.)
b. can use many other adjectives in this way: kind, clever, sensible, mean, silly, stupid, careless, unfair, considerate. (e.g. It’s silly of Mary to give up her job when she needs the money.)
G2. I’m sorry to ~/ I was surprised to ~ etc.
a. can use adjective + to say how somebody reacts to something (e.g. I was sorry to hear that your father is ill.)
b. can use many other adjectives in this way: happy, glad, pleased, sad, disappointed, surprised, amazed, astonished, relieved. (e.g. Was Julia surprised to see you?)
G3. The first/ the next (etc.) + to~
a. can use to ~ after the first/ the last, the next, the only, the second (etc.) (e.g. If I have any more news, you will be the first (person) to know.)
G4. can say that something is sure/ certain/ likely/ bound to happen. (e.g. Carla is a very good student. She’s bound to pass the exam. (= she is sure to pass))