Remember this

A gerund is a verb + ing.

A gerund can appear after prepositions (on, in, at, by, before, after, for, without...) for example,

She is good at (speak/ to speak/ speaking) English.
He is interested in (playing/ to play/play) musical instruments.

It can take place also in the beginning of sentences, for example:

(Jog) Jogging is a good hobby.
(Eat) Eating fast food is unhealthy.

A gerund can take place after certain phrases (look forward to, would you mind, feel like, can't stop, can't bear...etc.) and verbs like (enjoy, avoid, suggest, admit, regret, keep, imagine, deny, finish...), for example:

I'm looking forward to (help) helping you proofread the research paper.
Would you mind (clean) cleaning the board?
The kid enjoyed (watch) watching English cartoons.
The student avoided (meet) meeting the teacher in the corridor.

Bare infinitive is an infinitive without "to".

Bare infinitive is used after the following auxiliaries or modals: can, could, will, would, may, might, shall, should, must, 'd better, needn't... besides the verbs "let" and "make". For example,

You'd better (exercise/ to exercise/ exercising) regularly and eat fruit.
The driver must (stopping/ stop/ to stop) when the light turns red.
"Let the kid (eating/eat/ to eat) by himself," the father said.
The mother made her daughter (crying/ cry/ to cry).
Daniel needn't (watering/ water/ to water) the plants today.

An Infinitive is to + the base form of the verb.

The infinitive is used after a number of verbs such as want, need, decide, choose, plan, agree, promise, refuse, manage, expect, hope, attempt, pretend, afford, try, would like, don't forget... etc, for example:

The receptionist refused (to carry/ carry/ carrying) the baggage of the tourist.
He managed (solving/ solve/ to solve) the Math equation without calculator.
I can't afford (to buy/ buying/ buy) such a lovely car.

Verbs followed by Gerund

suggest, keep, avoid, miss, feel like, enjoy, mind, can't help, can't stand. (Prepositions are: on, in, at, by, before, after, about, to, with, of, from, without, off, up).

Verbs followed by Bare Infinitive

can, could, will, would, shall, should, may, might, had better, must, make, let, help, needn't. For example: He must call.

Verbs followed by Infinitive (to + verb)

decide, ask, agree, manage, want, need, invite, hope, promise, don't forget, refuse, advise, choose, learn, know, plan, can't afford. For example: He refused to sign the document.

Verbs followed by either Gerund or Infinitive

begin, stop, love, like, prefer, forget, remember, start. Note: Some verbs can be followed by either gerund or infinitive with a change in meaning, while others keep the same meaning.

I remember going to the countryside. (Means I have a memory of visiting the village).
I remembered to buy soda. (Means I was on my way home and the idea of buying soda came into my mind, so I bought it).
Whereas this example keeps the same meaning: I like eating fish = I like to eat fish.

Practice Exercises

Exercise 1
Give the correct form of the verbs in brackets.

I'm looking forward to (meet) ________________________ the boss soon.
He finished (build) ________________________ his new house.
Thank you for (come) ________________________ tonight.
I'll be back in a second; keep (work) ________________________
Avoid (eat) ________________________ fatty food; it's unhealthy.

Exercise 2
Give the correct form of the verbs in brackets.

You'd better (to study) ________________________ hard this year.
She might (to accept) ________________________ the job offer.
We should (to leave) ________________________ the office now.
He needn't (to buy) ________________________ more milk.
Tom will (to call) ________________________ you tomorrow.

Exercise 3
Give the correct form of the verbs in brackets.

The doctor advised her (eat) ________________________ vegetables.
My wife encouraged me (save) ________________________ more money
The teacher asked him (write) ________________________ the date.
The lady can't afford (pay) ________________________ the extra hours.
He planned (go) ________________________ for a hike next week.

Exercise 4
Give the correct form of the verbs in brackets.

He must (to respect) ________________________ the law.
He's fed up with (listen) ________________________ to Rock music.
The girl is afraid of (touch) ________________________ the lion.
He finally chose (buy) ________________________ the red car.
Would you mind (lend) ________________________ me your pen?
I find it difficult (solve) ________________________ this problem.

Exercise 5
Choose the right answer.

My friend stopped ________________________ last month. (quit smoking)
- a) smoking
- b) to smoke
I stopped ________________________ a hitchhiker. (I was driving and I saw him)
- a) to pick up
- b) picking up
She forgot ________________________ her medication. (She had the intention, but she didn't remember.)
- a) to take
- b) taking

Quiz 3: Quiz on Gerund, Bare Infinitive & Infinitive

Exercise 1
Fill in each gap with the appropriate word from the list. (10 Pts)

I am looking forward to ________________________ the new teacher. (meet - meeting - to meet)
The Browns have finished ________________________ for the wedding. (to prepare - prepare - preparing)
They agreed ________________________ a new cinema club in our school. (to set up - set up - setting up)
I wanted ________________________ to the stadium but I didn't get a ticket. (to go - go - going)
The student finally admitted ________________________ in the exam. (cheat - cheat - cheating)
You'd better ________________________ a doctor before taking that medication. (visit - to visit - visiting)
I enjoy ________________________ to classical music. (listen - listen - listening)
We have decided ________________________ to the beach this weekend. (to go - go - going)
He prefers to ________________________ in the countryside. (to live - live - living)
She is interested in ________________________ piano. (to play - play - playing)

Exercise 2
Give the correct form to the verbs in brackets. (5 Pts)

He apologized for not (show) ________________________ up in the wedding party.
The Spanish authorities forced some illegal immigrants (leave) ________________________ the country.
People should (use) ________________________ solar energy to protect the environment.
The countrymen are looking forward to (meet) ________________________ the new president.
"Stop (make) ________________________ the noise," the teacher shouted.
Although he is poor, he insists on (wear) ________________________ new clothes.
"(Buy) ________________________ smart phones is a waste of money," said the father to his son.
I really don't know how (answer) ________________________ this question.
Before (send) ________________________ the application letter, write your full name and sign it.
How about (plant) ________________________ some trees and flowers in our school garden.

Exercise 3
Fill in the blanks with the right answer from the list. (5 Pts)

Julia ended up ________________________ a new car after her old Volvo broke down.
- a) buying
- b) to buy
Our neighbour agreed ________________________ us his truck for a couple of days.
- a) to lend
- b) lend
He suggested ________________________ to the night club last night.
- a) go
- b) going
You'd better ________________________ a mechanic before buying this car.
- a) consult
- b) consulting
Have you finished ________________________ the questionnaire paper?
- a) filling in
- b) fill in
"It may ________________________ today," the weather man said.
- a) raining
- b) rain
The teacher let the student ________________________ early yesterday before 6 p.m.
- a) leave
- b) to leave
________________________ causes many fatal diseases namely lung cancer.
- a) smoke
- b) Smoking
Instead of ________________________ cards, why don't you read an interesting novel?
- a) playing
- b) play
I can't afford ________________________ a new house in the city.
- a) buy
- b) to buy

Check your answers here

Gerund, Bare Infinitive & Infinitive