摘要：49．In the story the woman didn’t find Bruce’s mother because .A. she went to the wrong house B. she didn’t know Bruce’s motherC. Bruce was not at home D. Bruce didn’t have a mother(B)The word “day has two meanings. When we talk about the number of days in a year, we are using “day to mean 24 hours. But when we talk about day and night, we are using “day to mean the time between sunrise and sunset. Since the earth looks like a ball, the sun can shine on only half of it at a time. Always one half of the earth is having day and the other half night. A place is moved from day into night and from night into day over and over by the spinningof the earth. At the equatorday and night are sometimes the same length. They are each twelve hours long. The sun rises at 6 o’clock in the morning and sets at 6 o’clock in the evening. For six months the North Pole is tiltedtoward the sun. In those months the Northern Hemispheregets more hours of sunlight than the Southern Hemisphere. Days are longer than nights. South of the equator nights are longer than days. For the other six months the North Pole is tilted away from the sun. Then the Southern Hemisphere gets more sunlight. Days are longer than nights. North of the equator nights are longer than days. Winter is the season of long nights. Summer is the season of long days.

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