https://agendaweb.org/exercises/verbs/infinitive-gerund/exercise-1
https://agendaweb.org/exercises/verbs/infinitive-gerund/exercise-2
https://agendaweb.org/exercises/verbs/infinitive-gerund/exercise-3
https://www.ego4u.com/en/cram-up/grammar/infinitive-gerund/exercises?04
https://www.ego4u.com/en/cram-up/grammar/infinitive-gerund/exercises?05
