You need a list of phrasal verbs. They look like verbs + prepositions, but they are verbs + particles. They can't be separated, so "keen on" is the whole verb phrase keen on + sports not keen + on sports.
Type in "phrasal verb list" on google and you'll get several pages.
Here's a list And here's another You can find literally hundreds or thousands of lists of phrasal verbs on google. When you are searching, add words like list and/or esl to help your search be more specific.
Student or Learner