國中英語基測出現過 but 的考題。

Dear Mr. Hush,

I just learned over the radio that you feel as bad as I do about the way people use their cellphones. Very often in public places, people speak loudly on their cellphone, and we have to hear about other people’s business. But who cares about that? Not me! Why should I know the life of people I don’t even know? It’s really nice that someone famous like you speaks out for a quiet living space.

And it’s even more wonderful to know that you yourself always talk quietly when you have to use the cellphone in public places. Thanks for NOT sharing what you are talking about. We have shared too much noise already!

A Person on Your Side

1.
What does that mean in the letter?
Being quiet.
Talking with strangers.
The cellphone.
Others’ business.
2.
What does the writer means by saying “Thanks for NOT sharing what you are talking about”?
It is dangerous to say something important over the cellphone in public places.
It is polite to use a low voice when you talk on the phone in public places.
It is wrong to listen to others talking on the phone.
It is kind to forget about other people’s mistakes.