The main reason why you would use the revising strategy called Use Snapshots is because snapshots are some of the easiest way to catch and contain lots of material, especially on a computer desktop.
Use slader. It tells u the answers. You just have to search the book up.
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.