In the old days, in London, the smog (烟雾) was very thick. Drivers had to drive very s【小题1】. It was hard for them to see the road in front of them even during the daytime. People did not like going out in the smog. I【小题2】 they had to go out, they wore masks (面具) over their faces.

In December 1952, a very thick dark cloud came down over London. It was the heaviest smog Londoners had ever had. About fifty people d【小题3】 in road accidents. And many people became unhealthy. The smog was very b【小题4】 for old people and children. One man said, “The s【小题5】 were almost empty because people stayed at home as much as possible. The air was very thick, and you could almost cut it with a knife.”