Your student's sentence is not quite right. It should be something like:I get used to watching TV.
(note used not use)
Actually, although this is now grammatically correct, it is not very idiomatic or probable. The present continuous would more likely be used:I am getting used to watching TV.
This structure can be used in any tense, for example:You will get used to watching TV.
He got used to watching TV.
They were getting used to watching TV.
The above structure (to get used to [doing] something
or to be used to [doing] something
should not be confused with used to do
."Used to do" or "Be used to" Quiz
may be helpful.