be strong on something
1. To excel at something. I'm not too strong on organic chemistry, so I'm going to get a tutor this semester.
2. To contain or display a lot of something. If you want an A on your term paper, it better be strong on literary theory.
be ˈstrong on something
1 be good at something: I’m not very strong on dates (= I can’t remember the dates of important events).
2 have a lot of something: The report was strong on criticism, but short on practical suggestions.