题目

下列说法中正确的是（ ）A.若，则 B.若，则C.若，则 D.若，则 答案：【答案】C【解析】利用不等式性质,及特殊值法可依次判断四个选项.对于A,当时,满足,但是错误,所以A不正确;对于B,当时, ,所以B不正确;对于C,若,则,不等式两边同时除以可得,所以C正确;对于D,当时,若,则,所以D错误.综上可知,C为正确选项.故选:CAt 9 a.m. on October 15, 2003, our country launched (发射) its first manned (有人的) space-ship, Shenzhou V, into space at Jiuquan Satellite Launch Center in Gansu Province. It took Yang Liwei and his spaceship about 21 hours to circle the earth 14 times. Yang Liwei is China’s first astronaut. He comes from Liaoning Province, and he has been an air force pilot(飞行员) since 1983. He was chosen from 14 pilots after many difficult tests.The life of an astronaut is hard to imagine for many people. To put on a space suit takes 15 minutes with the help of others. Sleeping in space is not easy, either. He has to sleep in a special sleeping bag on the wall because there is no gravity. Yang can eat chicken and rice. It’s especially made to eat in space but it doesn’t taste nice.“I’m feeling very good in space, and it looks wonderful here,” said Yang, “I have looked at our beautiful earth and I have recorded all that I have seen here.”China has become the third country in the world to send a person into space after the former Soviet Union(前苏联) and the United States. China is now planning its next launch. Shenzhou VI will be into space within(在……之内) the next years, it may take three astronauts. We are all proud of our motherland.【小题1】Shenzhou V was launched into space _____.A．at 9 a.m. on October 15, 2003B．at 9 p.m. on October 15, 2003C．at 9 a.m. on October 16, 2003D．at 9 p.m. on October 16, 2003【小题2】Yang Liwei is a(n) ______.A．policemanB．businessmanC．doctorD．astronaut【小题3】Yang Liwei is from _______.A．LiaoningB．GansuC．JiningD．Inner Mongolia【小题4】Which of the following is true?A．It took Yang Liwei and his spaceship about 12 hours.B．Life in space is easy for an astronaut.C．China is planning its next launch now.D．Yang Liwei is the first man into space.【小题5】We can know there are _____ countries in the world which can send man into space.A．fiveB．fourC．threeD．two