Infinitives and Gerunds

Infinitive

There are two forms of the infinitive.

We use:

The full infinitive (to + verb)

• to express purpose. - Jessie went to the library to borrow a book.
• after the verbs: want, would like, hope, decide, manage, plan, arrange, advise, choose, learn, offer, promise, refuse, expect, etc. - Betty offered to help me with my homework.
  
• after be + adjective. - It's good to exercise.
• after the adjectives: afraid, surprised, free, glad, happy, ready, sorry, please, etc. - Are you ready to begin?
• after too and enough. - This coffee is sweet enough (for me) to drink.

The bare infinitive (without to)

• after modal verbs (can, could, will, would, shall, should, may, might, must). - Shall we go now.
• after the verbs let and make (in active voice). - My parents don't let me stay out late.
  

-ing form (gerund)
It is used:

• after verbs which express preference: like, dislike, love, hate, enjoy, prefer, adore, etc. - Dan doesn't like dancing. He prefers listening to music.
• after verbs which express beginning or end: begin, start, stop, finish, continue, etc. - They started going out together when they were eighteen.
• after the verbs: avoid, forgive, imagine, remember, practice, suggest, mind, keep, etc. - Fay kept getting in the way.
• with expressions: can't help, can't stand, it's no good, how/what about...?, look forward, etc. - I can't stand eating beans.
• after prepositions: - He's thinking about parachuting lessons.
• as a subject of a verb: Eating fish is something I like doing when I go to an island.

Note: after the verb stop we can have a full infinitive or an ing form (gerund), but the meaning is different. Sandra stopped to buy some bread on her way home.(= She stopped another action because she wanted to buy bread.) She stopped buying bread from that bakery. (= She never again bought bread from that bakery.)

Making suggestions
To make a suggestion, we can use:

• can and could. - We can/could watch a video tonight if you like.
• shall we...? - Shall we invite Mark and Pauline for dinner next Saturday?
• expressions like: Let's..., How about...?, What about...? Why don't you...? - There's nothing to do here, Let's go for a walk.

Note: After How about...? and What about...? we use an -ing form (gerund) or a noun.