The main clause is "Chris's chief interest was tennis".
The subordinate clause is "Which he was just learning to play" and it is an adjective clause because it describes what the "tennis" was like. Tennis is an object and this subordinate clause further describes that it is the tennis that he was trying to learn.
Hello. You forgot to show the story to which this question is related, which makes it impossible for it to be answered accurately. However, I will try to help you in the best possible way.
It is only possible to know the veritable and unbelievable events by reading the text, however, we can consider that logical and credible are the events that you think would be possible to happen in the real world. The unbelievable events, on the other hand, are those that you don't believe are likely to happen.
