Gerunds & Infinitives

A gerund is the -ing form of a verb used as a noun. An infinitive is the to + base verb form. Knowing when to use each one is essential for writing accurate, natural sentences.

What You'll Learn

• How to form and recognise gerunds (verb + -ing used as a noun)
• How to use gerunds after certain verbs (e.g., enjoy, avoid, consider)
• How to use gerunds as subjects and as objects of prepositions
• How to choose between a gerund and an infinitive after specific verbs

When to Use

1. Gerund as the subject of a sentence: "Swimming is my favourite sport."
2. Gerund after certain verbs: "She enjoys reading mystery novels."
3. Gerund after a preposition: "He is interested in learning about science."
4. Infinitive after certain verbs: "They decided to visit the museum."
5. Gerund or infinitive with meaning change: "He stopped talking." vs "He stopped to talk."

How to Form

Forming Gerunds

Take the base verb and add -ing. The gerund looks the same as the present participle, but it functions as a noun, not a verb.

Spelling rules for adding -ing:

Forming Infinitives

Use to + base form of the verb. The infinitive does not change regardless of subject or tense.

Key Rules

1. Gerund as subject: When a verb-action is the subject of a sentence, use the gerund form. "Cycling to school saves money." (Not: To cycle to school saves money.)

2. Gerund after prepositions: After any preposition (in, at, of, about, for, without, before, after), always use the gerund. "She is afraid of flying." "Thank you for helping."

3. Gerund-only verbs: Some verbs must be followed by a gerund, never an infinitive. The most common are: enjoy, avoid, consider, finish, mind, practise, suggest, keep, imagine, miss, risk, deny, admit, delay, give up.

   • "I enjoy painting." (Not: I enjoy to paint.)

4. Infinitive-only verbs: Some verbs must be followed by an infinitive, never a gerund. The most common are: want, hope, decide, plan, agree, choose, expect, learn, need, offer, promise, refuse, seem, wish, would like.

   • "She decided to stay." (Not: She decided staying.)

5. Verbs that take both (same meaning): Some verbs can take either a gerund or an infinitive with no change in meaning: begin, start, continue, like, love, hate, prefer.

   • "He started singing." = "He started to sing."

6. Verbs that take both (different meaning): A few verbs change meaning depending on whether a gerund or infinitive follows:

   • remember + gerund = recall a past action: "I remember locking the door." (I recall that I locked it.)
   • remember + infinitive = not forget to do something: "I must remember to lock the door." (I must not forget.)
   • stop + gerund = quit doing something: "She stopped eating sweets." (She no longer eats them.)
   • stop + infinitive = pause in order to do something: "She stopped to eat lunch." (She paused so she could eat.)
   • try + gerund = experiment with a method: "Try adding more salt."
   • try + infinitive = make an effort: "He tried to lift the heavy box."

Common Mistakes

Clue Words

Gerund clue words (verbs that need -ing)

enjoy, avoid, consider, finish, mind, practise, suggest, keep, imagine, miss, risk, give up, can't help, feel like, it's no use, it's worth

Infinitive clue words (verbs that need to + verb)

want, hope, decide, plan, agree, choose, expect, learn, need, offer, promise, refuse, seem, wish, would like

Prepositions that signal a gerund

in, at, of, about, for, without, before, after, by, instead of, interested in, good at, afraid of, look forward to, used to (meaning accustomed to)

Tip: If you see a preposition before the verb, you almost certainly need the gerund (-ing). Watch out for "look forward to" and "used to (accustomed to)" -- the "to" is a preposition, not part of an infinitive!

Practice Tips

1. Memorise the common gerund-only verbs: Learn the list (enjoy, avoid, consider, finish, mind, practise, suggest, keep) as a group. Try making a sentence with each one.

2. Preposition check: Whenever you spot a preposition before a verb, switch to the gerund form. Ask yourself: "Is there a preposition (in, at, of, for, about) right before this verb?"

3. Meaning-change test: For verbs like remember, stop, and try, ask yourself: "Am I talking about something that already happened (gerund) or something I need to do next (infinitive)?"

4. Subject test: If a verb-action is the subject of the sentence, convert it to its -ing form. "Read is fun" sounds wrong; "Reading is fun" sounds right.

Quick Reference