1. He promised to write... Words such as promises, agreements, orders, offers, requests, advice, and suggestions are often reported with infinitives. |
Examples: He agreed to pay the bill. She promised to clean her room. They agreed to change the color. |
With words ask, advise, tell, and order are used with the structure object +infinitive (but not with promise or offer). |
Examples: I told her to wait for me. She advised me to apply for the position. The manager ordered Jeff to train the new staff. |
2. He asked her how to... It is common to use question word + infinitive structure. |
Examples: Don't tell her where to study. I didn't know whether to agree or not. She asked him how to open the bottle. |
3. Suggest, say: infinitives not used After the words suggest or say, infinitive structure isn't commonly used. Instead, that-clause is used with modal verbs. |
Examples: I told Will that he ought to be patient. The police said that I musn't drive too fast. I suggested that they should change the venue. |
It's also possible to use subjunctives and -ing structure after some verbs. |
Examples: I suggested trying the exam. I suggested that he try taking the exam. |