Exercise 7.6: Explian the reason why the underlined words are v+infinitives with to or v+ infinitive without to or v+ing forms

Exercise 7.6: Explian the reason why the underlined words are v+infinitives with to or v+ infinitive without to or v+ing forms. The following sentences come from the reading passage of this unit.

Children must learn to have their own opinions and to make their own decisions. One way that they learn this is to have their own rooms. Many American children have to take part-time jobs. These jobs help the children to get used to making a little money. A job helps teach the children to be responsible for their own actions and to choose between right and wrong. They often work in stores, offices, or restaurants to help pay for their college education. American parents expect each child to choose his or her own career or profession. Most children don't opt to follow in the foot steps of their parents; that is, they usually look forward to doing a different kind of work. Most Children seem to leave the nest when they are between the ages of eighteen and twenty-one. Some stay at home longer, and some return home if they have trouble finding work.         Answer:           learn to do someting [One way that they learn this] + is + to do something have to + V1 help + someone + to do something,  get used to + V ing help + V1 + noun + to + V1 in order to + V1 expect + someone + to do something opt to + V1, look forward to + V ing seem to + V1 have trouble + V ing