мест. тк. им.
what
каков результат? — what is the result?
каков он собой? — what does he look like?, what's he like to look at?
трудно сказать, каковы будут последствия — it is difficult to say what the consequences will be
каков! — how do you like him!
вот он каков! разг. — what a chap / fellow!