题目内容
假设磁盘上每个磁道划分成9个物理块，每块存放1个逻辑记录。逻辑记录R0，R1，…，R8存放在同一个磁道上，记录的安排顺序如表1-7所示。 表1—7记录的安排顺序 物理块 0 1 2 3 4 5 6 7 8 逻辑记录 R0 R1 R2 R3 R4 R5 R6 R7 R8 假定磁盘旋转一圈的时间为27ms，磁头当前处在R0的开始处。若系统顺序处理这些记录，使用单缓冲区，每个记录处理时间为3ms，则处理这9个记录的最长时间为 (11) ；若对信息存储进行优化分布后，处理9个记录的最少时间为 (12) 。
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It is quite reasonable to blame traffic jams, the cost of" gas and the great speed of modern life, but manners on the toad are becoming horrible. Eye,body knows that the nicest men would become fierce tigers behind the wheel. It is all right to have a tiger in a cage, but to have one in the driver’s seat is another matter. Road politeness is not only good manners, but good sense too. It takes the most cool-headed drivers great patience to give up the desire to beat back when forced to face rude driving. On the other hand, a little politeness goes a long way towards reducing the possibility of quarrelling and fighting. A friendly nod or a wave of thanks in answer to an act of politeness helps to create an atmosphere of good will and calmness so necessary in modern traffic conditions. But such behaviors of politeness are by no means enough. Many drivers nowadays don’t even seem able to recognize politeness when they see it. However, misplaced politeness can also be dangerous. Typical examples are the driver who waves a child crossing the street at a wrong place into the path of oncoming cars that may be not able to stop in time. The same goes for encouraging old ladies to cross the road wherever and whenever they want to. An experienced driver, whose manners are faultless, told me it would help if drivers learnt to correctly join in traffic stream without causing total blockages that give rise to unpleasant feelings. Unfortunately, modern drivers can’t even learn to drive,let alone master the roadmanship. Years ago, experts warned us that the fast increase of the car ownership would demand more give-and-take from all road users. It is high time for all of us to take this message to heart. Troubles on the road are often caused by______.
请列出5种基因定位或基因作图方法，并说明物理作图与遗传作图有何不同
It was very fine while I got up early last Sunday morning. 76. ______ So I decided to go for a walk and took some photos in the 77. ______ beautiful country. After breakfast, I carried my camera with 78. ______ me and set off. Everything went smooth. I enjoyed my trip 79. ______ so much that I didn’t realize the weather had been turned 80. ______ bad. I began to run and it was too late. I was caught 81. ______ by the rain and was wet through. I kept on running until 82. ______ I get to a bus stop. I stood there waiting a long time for the bus 83. ______ shivering (颤抖) with cold. Shortly before I got home, I 84. ______ had high fever, which made me stay in bed for a whole week! 85. ______
The largest earthquake (magnitude里氏9.5 ) of the 20th century happened on May 22, 1960 off the coast of South Central Chile.It generated (生成) one of the most destructive Pacific-wide tsunamis (海啸). Near thegenerating area, both the earthquake and the tsunami were very much destructive, particularly in the coastal area from Concepcion to the south end of Isla Chiloe. The largest tsunami damage occurred at Isla Chiloe-the coastal area closest to the epicenter(震中). Huge tsunami waves measuring as high as 25 meters arrived within 10 to 15 minutes after the earthquake, killing at least two hundred people, sinking all the boats, and flooding half a kilometer inland.There was large damage and loss of life at Concepcion, Chile’s top industrial city. Near the city of Valdivia, the earthquake and following aftershocks generated landslides which killed 18 people. At the port city of Valparaiso, a city of 200,000, many buildings collapsed. A total of 130,000 houses were destroyed--one in every three in the earthquake zone and nearly 2,000,000 people were left homeless.Total damage losses, including to agriculture and to industry, were estimated(估计) to be over a half billion dollars. The total number of deaths related with both the tsunami and the earthquake was never found accurately for the region. Estimates of deaths reached between 490 to 5,7002 with no distinction(差别) as to how many deaths were caused by the earthquake and how many were caused by the tsunami. However, it is believed that most of the deaths in Chile were caused by the tsunami. What can we learn about the tsunami waves generated by the earthquake（）
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