"weak in" vs "weak at"

English as a Second Language English Vocabulary, Grammar and Idioms
1

Do we say ‘weak in’ or ‘weak at’ English?
Also ‘strong in’ or ‘strong at’?

Many thanks.

2

Hi,
You can use ‘in’ or ‘at’ after ‘weak’, eg: I’m weak in/at English.
And you can say: I’m weak in English but strong in biology.