小刚家准备建一栋新房,爸爸买了一堆材料相同的石子,小刚选取一块石子在实验室测它的密度.
他先将托盘天平放在水平桌面上,调节托盘天平平衡时,发现指针停在分度盘的右侧,要使天平平衡,应将横梁右端的平衡螺母向   (左/右)移动;当他用天平测物体质量时,发现指针偏向分度盘的左侧,这时应该在天平右盘中      (增加/减少)砝码;
测小石子的密度,主要实验步骤是: A.用量筒测出小矿石的体积;B.将小矿石从水中取出,立即放在已调节平衡的天平盘上,加减砝码和调节游码,测出小矿石的质量;C.再用密度计算公式求出小石子的密度.请你评估:这一实验过程测算出的密度结果______(选填“偏大”、 “偏小”或“准确”),原因是_______________________.

刚按图甲所示的方法测石子的质量,请指出操作中的三个错误:
                                                      
                                                      
                                                      
纠正错误后继续实验,当盘中所加砝码和游码位置如图19乙所示时天平平衡,则此石子的质量为      g.在量筒内装有一定量的水,该石子放入前、后的情况如图19丙所示,则石子的体积是       cm3,此石子的密度是           kg/m3
Reading is very important. World Book Day falls on April 23 every year. It encourages people, especially teenagers, to discover the pleasure of reading. It is also the day to honor (尊敬) great writers.
Many countries celebrate (庆祝) World Book Day. On that day, millions of school children can buy books at a much lower price than usual in any bookstore in England. It has been done every year since 1998. World Book Day is also celebrated in China. Wen Jiabao, Premier of China, is an avid reader. He does lots of reading every day though he is very busy. On World Book Day 2009, he called on (号召) people to do more reading. Wen suggested that young people should spend more time reading. “Books can not change the world, but people can change the world by changing themselves through reading,” he said.
Reading helps us become more knowledgeable and smarter. Reading helps us to follow the latest developments of science and technology (技术). Reading gives us information about other cultures and places in the world. Reading is also one of the most important ways to learn a foreign language like English. We all know that it is difficult to learn everything in the classroom, for example, the ways English people are living and working today can be learnt by reading.
Books, magazines, newspapers and other kinds of reading materials can help us to know more about the outside world. Therefore, it is necessary for us to spend time reading every day.
【小题1】When is World Book Day?                                
A.August 8 every year. B.March 12 every year.
C.April 23 every year.D.June 6 every year.
【小题2】An avid reader is a person who __________.
A.loves readingB.never readsC.does some readingD.hates reading
【小题3】World Book Day was set up in order to encourage people to __________.
A.learn foreign languagesB.do more reading
C.buy more booksD.know more about science
【小题4】According to the passage, reading can help people in many ways EXCEPT _____.
A.learning English betterB.knowing more about cultures
C.improving your healthD.knowing more about the outside world
【小题5】What’s the best title for the article?
A.World Book Day in England.
B.Suggestions on Reading.
C.World Book Day in China.
D.World Book Day and the Advantages of Reading.

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