| 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. So [单选题]持久黄体发生的主要原因是下列哪种激素分泌量不足（60）
A.雌二醇 B.雌三醇 C.孕酮 D.前列腺素 [单选题]典型的三叉神经痛不包括
A.阵发性剧痛 B.扳机点 C.痛性抽搐 D.夜间发作多见 E.病程可是周期性发作 [简答题]质点沿直线运动，加速度a＝4-t2，式中a的单位为m•ｓ-2，t的单位为ｓ．如果当t＝3ｓ时，x＝9m，v＝2m•ｓ-1，求质点的运动方程．
[判断题]当带电冲洗水压不足时，不得将水枪对准被冲洗的带电设备。
A.正确 B.错误 [判断题]签订供用电合同的用电单位和供电企业双方都是电力法律关系的主体。
A.正确 B.错误 [单项选择]对乙酰氨基酚用于治疗
A. 急性风湿热 B. 感冒发热 C. 预防血栓形成 D. 类风湿性关节炎 E. 急性痛风 [单选题]竹茹的功效是
A.清肺化痰、清心定惊 B.清热化痰，利咽排脓 C.清热化痰，止呕、安胎 D.清热化痰，利水消肿 E.清热化痰，凉血止血 [单选题]试验中如发生异常情况，应立即（），并经充分放电、接地后方可检查。
A.断开电源 B.远离现场 C.报告 D.结束试验 [单选题](47595).在直线上的超高顺坡,有缓和曲线时不得大于( )mm。(1.0分)
A.8 B.10 C.15 D.25 我来回答: 提交
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