Question

Which phrase from the passage acknowledges a contrasting thought and signals that the author will repeat the main point

Answer 1

However and On the Contrary are signal contrasting words. It would help to include the sentences in the question to be in order to provide an accurate answer.

Answer 2

The phrase from the passage that acknowledges a contrasting thought and signals that the author will repeat the main point is "however, I still."
So, in the beginning of the passage, the author stated that his favorite thing to do is watch TV. He moves on to elaborate that he knows that it's not a good thing to do it a lot. And then he uses the phrases "however, I still" to repeat that he loves TV and that he will still continue watching it, even though it may not be good for him or her.