Good at something

B1- B1 B2 C1

WRONG: I am really good in tennis.
RIGHT: I am really good at tennis.

Prepositions can be a big problem when Czechs try to speak English – mainly because they are usually different in each language. A really common mistake is saying ‘in’ instead of ‘at’ when it comes to ability.

It is wrong to say you are good ‘in’ something. Correct is to say you are good ‘at’ something.
This is true whatever adjective you use. So, we say, bad at, terrible at, amazing at, or simply ok at.

For example:

A: Are you good at dancing?
B: No, I am terrible at dancing. But I am good at drinking! Let’s go and get another beer.