Have you done a lesson on infinitive phrases yet? These can be taught one step at a time.
1) I love to travel. (infinitive phrase as object) 2) I love for you to scratch my back. (infinitive phrase as object of preposition - for. The infinitive has a subject - you) 3) I helped him to wash the dishes. (infinitive with a subject - him; object of the verb helped.
A few verbs (hear, see, feel, overhear, observe, watch, etc) can be either followed by an -ing form or bare infinitive, but themeaning might be slightly different.
I watched them building the house(suggeststhat we watch, etc, some of the action, but not from start to finish)
I watched him climb (suggests thatwe watch, hear, etc., the whole action from its start to it