Read the text then choose the best answer to fill in the blank.I often hear or read about “natural disasters” – the eruption of Mount St. Helen, a volcano in the state of Washington; Hurricane Andrew in Florida; the floods in the American Midwest; terrible all over the world; huge fires; and so on and so on. But I’ll never forget my first personal experience with the strangeness of nature – “the London Killer Fog” of 1952. It began on Thursday, December 4, when a high – pressure system (warm ...

Read the text then choose the best answer to fill in the blank.

I often hear or read about “natural disasters” – the eruption of Mount St. Helen, a volcano in the state of Washington; Hurricane Andrew in Florida; the floods in the American Midwest; terrible all over the world; huge fires; and so on and so on. But I’ll never forget my first personal experience with the strangeness of nature – “the London Killer Fog” of 1952. It began on Thursday, December 4, when a high – pressure system (warm air) covered southern England. With the freezing – cold air below, heavy fog formed. Pollution from factories, cars, and coal stoves mixed with the fog. The humidity was terrible high, there was no breeze at all. Traffic (cars, trains, and boats) stopped. People couldn’t see, and some walked onto the railroad tracks or into the river. It was hard to breathe, and many people got sick. Finally, on Tuesday, December 9, the wind came and the fog went away. But after that, even more people got sick. Many of them died.

Which “natural disaster” isn’t mentioned in the text?