A common English sentence pattern is:
Subject + predicate + object
The subject and the object must be a noun or a pronoun; the predicate must be a verb. If you have to use a verb as the subject or the object in a sentence, you must change this verb into an infinitive or a gerund. That is, you have to put “to” before the verb (infinitive), or add “ing” to the end of the verb (gerund).
When we use a non-verb form (infinitives and gerunds) as an object, we need to be careful because some verbs must be followed by a gerund and some verbs must be followed by an infinitive.
I enjoy music. (correct)
I enjoy listening to music. (correct)
I enjoy to listen to music. (incorrect)
I enjoy listen to music. (incorrect)
I decided to go home early today. (correct)
I decided go home early today. (incorrect)
I decided going home early today. (incorrect)
Here are three important lists of verbs:
a) Verbs that can be followed by both infinitives and gerunds
(These last 4 verbs can be followed by both, but the meanings are different.)
b) Verbs that can only be followed by gerunds
(The following phrases must be followed by gerunds.)
it’s no use
have trouble (difficulty)
c) Verbs that can only be followed by infinitives
You can add more verbs to the lists, but I think these are the important verbs that students need to remember first.