In some cases but not all
Answer:
Rita got her dress washed.
This is true. A thesis statement is you opinion. This means that not everyone will agree with your opinion. For example:
Smoking should be illegal because it is unhealthy, costly, and an annoyance.
Though you supported your opinion, someone who enjoys smoking may say that it is not costly or annoying. This is why a thesis statement is controversial.
I think "that" is the adjective clause because you can remove it without ruining the sentence.
