Prepositions after interested, good, bad

What Are Dependent Prepositions?

Some adjectives in English always need a specific preposition after them. We call these dependent prepositions. You cannot change or remove them—they are fixed patterns. In this lesson, we focus on three very common adjectives: interested, good, and bad. Learning these patterns will help you speak and write more naturally.

Interested + IN

When you want to say that someone likes or wants to know more about something, use interested + IN. This is the most common pattern with 'interested'. After 'interested in', you can use a noun or a gerund (verb + -ing form).

Good AT / Bad AT

To describe someone's ability or skill, use good/bad + AT. This pattern shows what someone does well or poorly. After 'good at' or 'bad at', you usually use a gerund (verb + -ing form), but you can also use nouns.

Quick Memory Tip

Remember: INTERESTED = IN (both start with 'in'). GOOD/BAD = AT (when talking about ABILITY). Use these mental links to remember the correct prepositions.

Examples in Context

interested in

She has always been interested in learning new languages.

Use interested in + noun or gerund to describe a topic or activity that captures someone's attention.

Are you interested in joining our volunteer programme this summer?

Interested in + gerund is the standard pattern when the object is an action (joining, visiting, buying, etc.).

My brother is interested in vintage motorcycles and spends every weekend restoring them.

The preposition in is fixed with interested; no other preposition is correct here.

The investors are interested in acquiring a stake in the start-up.

In formal and business contexts, interested in signals intent or curiosity about an opportunity.

good at / good for

Marcus has always been good at maths, so studying engineering was a natural choice.

Use good at to describe a skill or ability someone possesses — their talent or proficiency in doing something.

She is surprisingly good at remembering names, even years after meeting someone.

Good at + gerund describes how well someone performs a specific action.

Regular exercise is good for both your physical and mental health.

Use good for when talking about what benefits a person, thing, or situation — not a personal skill.

This calcium supplement is good for strengthening bones and teeth.

Good for + gerund or noun phrase indicates a beneficial purpose or effect.

He is not particularly good at public speaking, but he practises every day to improve.

The negative form not good at works the same way — at always follows when describing ability or skill.

bad at / bad for

I'm really bad at keeping secrets — I always end up telling someone!

Just like good at, use bad at to describe a lack of skill or ability in a particular activity.

She admitted she was bad at managing her time and decided to take an online course.

Bad at + gerund is the natural pattern when the object is an action. Compare: good at managing vs bad at managing.

Eating too much sugar is bad for your teeth and can lead to serious health problems.

Use bad for — not bad at — when talking about something that has a harmful effect on a person or thing.

Staying up until 2 a.m. every night is bad for your concentration the next day.

Bad for expresses a negative impact or consequence, parallel to how good for expresses a positive one.

The new regulations could be bad for small businesses that cannot afford the compliance costs.

In more formal contexts, bad for describes a detrimental outcome for a group or entity, not a personal skill.

Formula

✔ Positive

Subject + is/am/are + interested + in + noun/gerund

I am interested in cooking.

? Question

Is/Are + subject + interested + in + noun/gerund

Are you interested in sports?

Signal words

interested in good at bad at very interested in quite good at really bad at

KEY TAKEAWAYS

What to Remember

Use interested + IN when talking about liking or wanting to know more about something.
Good + AT describes someone's skill or ability in doing something specific.
Bad + AT means someone is not skillful or doesn't perform well at something.
These dependent prepositions are fixed patterns; you cannot change or remove them.
Learning these three patterns helps you speak and write English more naturally and correctly.