u/ShadowyGamer13

Okay so, I am not a native speaker and my english exam results came in earlier this week. My teacher took a point from my answer because I used "is" instead of "are".

The sentence: There is a TV, a sofa and a coffee table.

I know that my answer was grammatically correct but I don't know how I can prove it.

She also took another point because I used "in there" in the following sentence:
"...because I can do my favorite activities in there."

She said that I should've just used "there" and dropped the "in" because they mean the same thing, but from my research using an extra "in" isn't wrong either.

Any ideas on what I can do to prove my point or am I just completely in the wrong?
(I also hate this teacher with all my heart.)