The core question: -ing or to?

Some verbs are followed by a gerund (verb + -ing), some by an infinitive (to + verb), and some accept both — sometimes with a change in meaning. There is no single grammar rule that predicts which form a verb takes; it depends on the main verb itself. That's the hard truth, and it's why this topic frustrates learners. But there are patterns worth knowing, and a short list of tricky verbs worth memorising.

Gerund = the -ing form used as a noun (swimming, reading, complaining). Infinitive = to + base verb (to swim, to read, to complain).

Verbs that take only one form

Some common verbs always want a gerund after them: enjoy, avoid, finish, mind, suggest, keep, practise, consider, deny, risk.

✅ She enjoys reading before bed. ❌ She enjoys to read before bed.

Other verbs always want an infinitive: want, need, decide, plan, hope, promise, agree, refuse, learn, seem, expect, afford, manage, offer.

✅ They decided to leave early. ❌ They decided leaving early.

A useful (imperfect) shortcut: verbs that describe reactions or ongoing feelings often take the gerund (enjoy, dislike, can't stand), while verbs that point forward to a future action or intention often take the infinitive (plan, hope, promise).

Verbs that take both — with a meaning shift

This is where B1–B2 learners lose marks. A handful of verbs change meaning depending on which form follows them.

Remember / Forget

• remember + gerund = you recall a past event: I remember locking the door. (I have a memory of doing it.)
• remember + infinitive = you don't forget a task: I remembered to lock the door. (I didn't forget; I did it.)

✅ I'll never forget meeting her for the first time. (a past memory) ❌ I'll never forget to meet her for the first time. (This implies a future task, which doesn't make sense here.)

Stop

• stop + gerund = quit the activity: He stopped smoking. (He no longer smokes.)
• stop + infinitive = pause in order to do something: He stopped to smoke. (He paused what he was doing so he could have a cigarette.)

Try

• try + gerund = experiment with a method: Try adding more salt.
• try + infinitive = make an effort: I tried to open the window, but it was stuck.

After prepositions — always the gerund

Any verb that comes right after a preposition (about, of, in, at, for, without, before, after…) must be in the -ing form. No exceptions.

✅ She left without saying goodbye. ❌ She left without to say goodbye.

This rule also applies to adjective + preposition combinations: interested in learning, good at cooking, tired of waiting.

The mistake that costs the most points

The single most common error at this level is using an infinitive after enjoy, suggest, or avoid — probably because the learner's first language uses an infinitive there, or because want to is learned early and its pattern feels "normal."

❌ I really enjoy to travel. ✅ I really enjoy travelling.

❌ She suggested to go to the beach. ✅ She suggested going to the beach.

If you can only memorise one thing from this page, make it this short list: enjoy, avoid, finish, suggest, mind, keep, practise → always -ing. Tattoo it on your brain. Everything else you can often reason through or look up, but these seven trip up more learners than all the others combined.