The adjectives good, bad and clever are usually followed by the preposition at. Note that ‘in’ is not used.
The expression good at is used to talk about things that you enjoy or excel at doing. After good at, we can use a noun or an –ing form. Note the preposition: we use at, not in.
I am good at tennis. (NOT I’m good in tennis.) (NOT I’m good with tennis.)
Is she good at singing?
She isn’t very good at cooking.
He is good at drawing.
She is very good at writing.
I’m not very good at singing.
Are you good at dancing?
That boy is quite good at sports.
I’m not very good at painting.
Bad at is the opposite of good at.
She is very bad at cooking. (= She can’t cook at all.)
I’m not bad at tennis.
Susie is bad at singing.
You are bad at planning.
Clever at has a similar meaning to good at.
She is very clever at cooking.
I’m not very clever at teaching.
Mike is very clever at tennis.
He is very clever at painting.
He is not very clever at math.