问题 实验题

为了提高螺旋测微器的读数精度,有人对螺旋测微器进行了这样的改进,在螺旋测微器固定刻度的上半部刻了 10个等分刻度,固定刻度的“横线”是10等分刻度的“0”刻度线,这10个分度的总长度与可动刻度的9个分度的总长度相等,如图所示。经过改进的螺旋测微器的精度为________mm,图中螺旋测微器的读数为_______mm。

答案

0.001(2分),5.783(3分)

千分尺即精度为0.001,读数:固定尺+可动尺=5.5+0.283=5.783(最末一位为估读值在2—5之间的数字均可)

阅读理解

Hi! Have you ever suddenly felt that someone you knew was in trouble — and was he? Have you ever dreamed something that came true later? Maybe you have ESP (超感觉知觉).

  ESP stands for Extrasensory Perception. It may be called a sixth sense. It seems to let people know about events before they happen, or events that are happening some distance away.

  Here's an example. A woman was ironing clothes. Suddenly she screamed, "My father is dead! I saw him sitting in the chair!" Just then, a telegram came. The woman's father died of a heart attack. He died sitting in a chair.

  There are thousands of stories like this one on record. Scientists are studying them to find out what's behind these strange mental messages. Here's another example—one of hundreds of dreams that have come true.

  A man dreamed he was walking along a road when a horse and carriage came by. The driver said, "There's room for one more." The man felt the driver seemed dead, so he ran away. The next day, when the man was getting on a crowded bus, the bus driver said, "There's room for one more."

  Then the man saw that the driver's face was the same face he had seen in the dream. He wouldn't get on the bus. As the bus drove off, it crashed and burst into flames. Everyone was killed!

  Some people say stories like these are coincidences. Others, including some scientists, say that ESP is real. From studies of ESP, we may someday learn more about the human mind.

小题1:According to the passage, the author believes that the sixth sense is ________.

A.in existence

B.imaginative

C.not real

D.impossible小题2:ESP lets people know _________.

A.about events before they happen 

B.about events after they happen

C.about events that are happening some distance away

D.A and C小题3:By studying ESP, scientists may get to ________.

A.learn how people tell lies

B.know more about human dreams

C.know more about human mind

D.learn how strange things happen小题4:In the last paragraph the underlined word "coincidences" probably means _______.

A.things that may not happen

B.things that happen in a dream

C.things that must happen

D.things that happen by accident

单项选择题