Gerunds after Prepositions

In English grammar, there is an absolute and unbreakable rule concerning prepositions (e.g., in, on, at, about, of, for, with, without, before, after, by):

The Preposition Rule: If a verb immediately follows a preposition, it must be written in the gerund (-ing) form. It can never be an infinitive or a base verb.

1. Adjective + Preposition Combinations

Many English adjectives are paired with specific prepositions. Any action following them must be a gerund.

  • Interested in: I am interested in learning photography. (Not: interested in to learn).
  • Good / Bad at: She is very good at solving math puzzles.
  • Excited about: They are excited about moving to a new city.
  • Afraid of: He is afraid of flying in airplanes.
  • Tired of: We are tired of waiting for the bus.

2. Verb + Preposition Combinations

Similarly, many verbs are followed by prepositions.

  • Apologize for: I apologize for being late.
  • Think about: She is thinking about changing her job.
  • Succeed in: They succeeded in climbing the mountain.
  • Dream of: He dreams of becoming an astronaut.

The “To” Preposition Trap: In phrases like look forward to or be used to, the word to is a preposition, not part of an infinitive. Therefore, it must be followed by a gerund.

  • Correct: I am looking forward to meeting you.
  • Incorrect: I am looking forward to meet you.

3. Prepositions of Method and Absence: “By” and “Without”

We frequently use by and without followed by a gerund to describe how an action is performed.

A. By + Gerund (Showing Method / How)

  • You can improve your English by practicing every day.
  • He turned off the television by pressing the main button.

B. Without + Gerund (Showing Absence of Action)

  • He walked out of the room without saying a word.
  • She solved the problem without using a calculator.

4. Summary Guide

Combination TypePatternExample
Adjective + Prepgood at + Verb-ingHe is good at drawing.
Verb + Preptalk about + Verb-ingThey talked about starting a business.
”To” as Prepositionlook forward to + Verb-ingI look forward to hearing from you.
Preposition of Methodby + Verb-ingLearn by doing.