阅读理解

    Light travels at a speed which is about a million times faster than the speed of sound. In one second, light travels about 300,000 km, but sound travels only 344m. You can get some idea of this difference by watching the start of a race. If you stand some distance away from the starter, you can see smoke come from his gun before the sound reaches your ears. This great speed of light produces some strange facts. Sunlight takes about 8 minutes to reach us. If you look at the light of the moon tonight, remember that the light rays（光线）left the moon 1.3 seconds before they reached you. The nearest star is so far away that the light which you can see from it tonight started to travel towards you four years ago at a speed of nearly 2 million km per minute. In some cases the light from one of tonight's stars started on its journey to you before you were born.

    Thus, if we want to be honest, we cannot say “The stars are shinning tonight.” We have to say, “The stars look pretty. They were shining four years ago but their light has only just reached Earth.”

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    In some provinces of Canada，people celebrate Family Day on the second Monday of February. It is a holiday that gives families the chance(机会)to 1together.

    On Family Day，many people plan and take part in(参加)activities such as visiting art museums，watching movies，playing games and holding parties，with their families. Some communities(社区)plan special public 2too.

    3the weather is usually very cold in February，some people 4choose to stay at home. Hot chocolate and freshly made cookies are the most popular snacks for

    5.Other people use the long weekend as a chance to take a short winter break，or to travel to visit friends.

    On Family Day，most people have a day off work or school. Many stores and supermarkets are 6，but post offices may be open. Buses run 7their usual timetables(时刻表).

    Family Day was first 8in Alberta，Canada in 1990.It was held to show the importance of family and home that were important to people in Alberta. Later，Family Day was9to other provinces，such as Ontario and Saskatchewan. British Columbia celebrated Family Day as a(n)10for the first time in 2013.One of the reasons for introducing Family Day was that there were no holidays from New Year's Day to Good Friday(受难节).It was such a long time.

下列不是人类面临的自然灾害的是（    ）