tom is really ... he always gets good merks in every test he does

Tom is really SMART he always gets good merks in every test he does

Tom sangat cerdas,dia selalu mendapatkan hasil/nilai bagus pada setiap test yang dia kerjakan.

tom is really clever (or you can put any other synonyms. something like: intelligent, educated, knowledgeable. or the typical, smart) he always gets good marks in every tests he does.