Each item in this section consists of a single sentence with four selected parts. Three of the selected parts are correct; one is incorrect. Here you must choose the selected part that is incorrect. Check particularly the following: (1) '-ing' form after prepositions; (2) that 'for to' does NOT occur; (3) the 'to + infinitive complement' of certain expressions (e.g. It is difficult to . . .); (4) that 'to' is not used after a modal, except for 'ought'; (5) that the form of the second verb is appropriate where two verbs occur together (e.g. He dislikes swimming; He wants to eat) where the first is not a modal.