题目内容

切削力的来源:(1)()和()抗力;(2)()、()与刀具之间的摩擦力。

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以下对于科研实践的说法,正确的是()。

A. 科研实践是整个学习阶段的最后一环
B. 科研实践的目的主要是通过实践来掌握科研的方法
C. 科研实践是对前一阶段学习的检验
D. 科研实践是为将来从事科研工作作准备

施工合同中关于项目经理的说法错误的是()。

A. 项目经理应常驻施工现场
B. 项目经理每月在施工现场时间不得少于专用合同条款约定的天数
C. 项目经理不得同时担任其他项目的项目经理
D. 项目经理确需离开施工现场时,应事先通知监理人,不必取得发包人的书面同意

Moderate Earthquake Strikes England A moderate earthquake struck parts of southeast England on 28 April 2007, toppling chimneys from houses and rousing residents from their beds. Several thousand people were left without power in Kent County. One woman suffered minor head and neck injuries. "It felt as if the whole house was being slid across like a fun-fair ride," said the woman. The British Geological Survey said the 4. 3-magnitude quake struck at 8:19 a.m. and was centered under the English Channel, about 8.5 miles south of Dover and near the entrance to the Channel Tunnel. Witnesses said cracks appeared in walls and chimneys collapsed across the county. Residents said the tremor had lasted for about 10 to 15 seconds. "I was lying in bed and it felt as if someone had just got up from bed next to me." said Hendrick van Eck, 27, of Canterbury about 60 miles southeast of London. "I then heard the sound of cracking, and it was getting heavier and heavier. It felt as if someone was at the end of my bed hopping up and down." There are thousands of moderate quakes on this scale around the world each year, but they are rare in Britain. The April 28 quake was the strongest in Britain since 2002 when a 4.8-magnitude quake struck the central England city of Birmingham. The country's strongest earthquake took place in the North Sea in 1931, measuring 6.1 on the Richter scale. British Geological Survey scientist Roger Musson said the quake took place on 28 April in an area that had seen several of the biggest earthquakes ever to strike Britain, including one in 1580 that caused damage in London and was felt in France. Musson predicted that it was only a matter of time before another earthquake struck this part of England. However, people should not be scared too much by this prediction, Musson said, as the modern earthquake warning system of Britain should be able to detect a forthcoming quake and announce it several hours before it takes place. This would allow time for people to evacuate and reduce damage to the minimum. The Channel Tunnel was closed for 10 hours after the earthquake occurred.()

A. Right
B. Wrong
C. Not mentioned

气压机出口冷却器冷却效果差,使压缩富气进塔温度较高,干气中C3含量增加。

A. 正确
B. 错误

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