[单项选择]

Everyone uses the expressions AM and PM. But do you exactly know what they mean and how they came into being
As you know, the turning of the earth makes the sun and the stars seem to move across the sky. Daylight, of course, (21) ,when the sun rises in the east and when the sun is high (22) the sky, between these two positions, half of the daylight hours have been spent.
Therefore, by noticing (23) the sun stood in the sky, early man know they could tell the time of the day. At night the motion of the stars (24) the same purpose. The important thing in keeping time is to know the exact moment of (25) . For each of us, wherever we are, noon is when the sun is directly overhead. Think of an imaginary line (26) the sky,, stretching from the north point of your horizon just to the south point.
When the sun cross your meridian (子午线), it is noon for you. When the sun still (27) of this line, or the m
A. in
B. shining
C. rising
D. falling

最新试题

• ●    [判断题]空调属于一级负荷中特别重要的负荷。（）
• ●    (2008，29)甲公司委托丙公司退休工程师乙开发一套计算机软件，但合同中没有就该软件著作权的归属做
• ●    人们形容英国早期的衡平法的诉讼程序时说“衡平法是‘大法官的脚’可大可小”，其含义最确切的是：
• ●    [多选题]在射电望远镜发明之前,许多星球就客观存在着,但它们没有成为认识的客体。射电望远镜发明之后才
• ●    [多选题]社会主义核心价值观是社会主义核心价值体系的 ( )
• ●    [多选题]工作票上应填写使用的接地线（）等随工作区段转移情况。