Gerund (-ing) and Infinitive

Have a look at the following exercises.
One. Gerund and infinitive.

Two. Prepositions and gerunds.
Three. Gerunds after prepositions.
Four. Gerund as subject or object.
Five. Forger, regret, remember, try, etc.
Six. Forget, regret, remember, stop, try, etc.
Seven. Infinitive or gerund?