题目

(7分)2010年4月，墨西哥湾的海底石油开采平台发生火灾，泄漏的石油造石油公司和科学家对泄露量上发生争论．小明认为应先测量石油密度才能估算他设计了如图所示的装置．在杯子内盛有适量石油，放入一个质量是5.6×10—3kg，边长是2cm的正方体物块，有3/4的体积浸没在石油中，此时石油深度为0.1m.。(g =10N／kg)(1)石油的密度为多少?(保留两位小数)(2)石油对杯底的压强是多少？        Do you know how to study better and make your study more effective(有效)? We all know that Chinese students usually study very hard for a long _______. This is very good, but it doesn't _______ a lot. For an effective student must have enough sleep, enough food, enough rest and exercise. Every day you need to go out for a walk or visit some friends or some nice places. It's good for your study. When you return _______your studies, your mind will be refreshed(清醒的) and you'11 learn more_______study better. Psychologists(心理学家) _______that learning takes place in this way. Here take English learning _______an example. First you make a lot of progress and you feel happy. Then your language study seems _______ the same. So you will think you're learning _______and you may give up. This can last for days or even weeks, yet you needn't give up. At some point your language study will take another big _______again. You'11 see that you really have been learning all along. If you get enough sleep, food, rest and exercise, studying English can be very effective and __________. Don't give up along the way. Learn slowly and you're sure to get a good result.1.A.days B.time C.house D.weeks2.A.help B.give C.make D.take3.A.after B.for C.at D.to4.A.yet B.and C.or D.but5.A.have found B.have taught C.told D.said6.A.with B.for C.as D.to7.A.to have B.to make C.to take D.to stay8.A.something B.anything C.nothing D.everything9.A.work B.jump C.walk D.result10.A.hard B.common C.interesting D.possible