A gerund is a verb ending in -ing functioning as a noun (e.g., Swimming is fun). An infinitive is to + base verb (e.g., I want to swim). Knowing when to use which is critical for natural English.
Verbs Always Followed by a Gerund (-ing)
Memorize these verbs: admit, avoid, consider, deny, enjoy, finish, practice, suggest, risk, postpone.
Correct: She avoided talking to strangers.
Correct: He admitted making a mistake.
Verbs Always Followed by an Infinitive (to + verb)
Memorize these verbs: agree, decide, hope, manage, plan, promise, refuse, want, afford.
Correct: They decided to leave early.
Correct: She promised to call me.
Verbs Changing Meaning with Gerund vs Infinitive
Stop doing: Cease an activity (He stopped smoking = quit the habit).
Stop to do: Pause an action in order to do another (He stopped to smoke = paused walking to have a cigarette).