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 (日出 and sunset (日落).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 spinning (旋转) of the earth. At the equator
(赤道) day and night are sometimes the same length (长度). 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 tilted (倾斜) toward the sun. In
those months the Northern Hemisphere (半球)gets 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.
单选题
There are 365 days in a year. How many hours are there in a day?
【正确答案】
A
【答案解析】根据第一行“When we talk about the number of days in a year，we are using‘day’to mean 24 hours．”可知一年365天中的“天”指的是24小时，而非“白天”的12小时，故选A。
单选题
When the Western Hemisphere is having day, the Eastern Hemisphere is having
【正确答案】
B
【答案解析】根据第三行“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．”可知地球是个球体，太阳每次只能照到它的一半，照到的一边是白天，另一边就是晚上，故选B。
单选题
We have days and nights because of _____of the earth.
【正确答案】
C
【答案解析】根据第五行“A place is moved from day into night and from night into day over and over by the spinning of the earth．”可知是地球的自转导致了日夜交替，故选C。
单选题
______ day is as long as night at the equator.
【正确答案】
A
【答案解析】根据第六行“At the equator day and night are sometimes the same length．”可知在赤道，有时日夜长度是相等的，故选A。
单选题
When the North Pole is tilted away from the sun, [A] days are as long as nights in Shanghai [B] nights are longer than days in Sydney [C] nights are longer than days in New York
【正确答案】
C
【答案解析】根据倒数第四行“For the others six months the North Pole is tilted away from the sun. Then the Southern Hemisphere gets more sunlight．Days are longer than nights．”可知北极偏离太阳的这半年，南半球照到更多阳光，日比夜长，北半球则相反，Shanghai和New York纽约在北半球，Sydney悉尼在南半球，故选C。