从A、B、C、D四个选项中，选出可以填人空白处的最佳选项，并在答题卡上将该项涂黑。
21．---Would you mind if I asked you where you’re from?
--- .
A．Of course. I’m from London. B．Sure. I was born in London.
C．Not really. You can do it. D．Not in the least. I’m from London.
22.When it air pollution, Beijing faces the three “C” s-----cars，coal and construction，which lead to Beijing's thick air pollution.
A. refers to B. comes to C. happens to D. speaks to
