通读下面短文, 掌握其大意然后在1—10题所给的A、B、C、D三个选项中, 选出一个最佳选项。

    The world 1 many interesting sounds. Some are unpleasant to our ears while 2 are very pleasant to hear. In single day you probably hear 3 sounds. All sounds are different. Some 4 loud, some sounds are high, others are low, some sounds are useful.

    5 sound we can't talk or listen to each other. The ringing of the alarm clock wakes people up. The hooting（鸣笛声）of a car warns people of danger.

    Some sounds are harmful. When planes fly low 6 the land; the very loud sounds can damage the house. Very loud sound can even make people deaf.

    We know sound travels about one kilometer in three 7. In a thunder（雷）storm you see the lighting first and then hear the thunder. This is because light travels 8 than sound.

    Next time you see lighting count the number of seconds before you hear the thunder.

    Divide（分成）this number 9 3. This will tell you 10 kilometers away the thunder storm is.