题目

化学方程式配平后，有时不需要在等号上方注明反应条件，这表明(    )     A．此化学方程式不完整        B．此反应在通常状况下可以发生     C．此反应不能发生              D．此反应方程式不符合质量守恒定律 答案：B任务型阅读When people succeed,it is because of hard work,but luck has a lot to do with it.Napoleon once said all the hard work and talent in the world can't make up for bad luck.However,hard work can invite good luck.When it comes to success,luck can mean being in the right place to meet someone.Nothing can replace hard work,but working hard also means you're preparing yourself for opportunity.How many of the great inventions and discoveries came about through a lucky mistake or a lucky chance?One of the biggest lucky mistakes in history is Columbus' so-called discovery of America.He changed history,but he was really looking for India.It was backed up by years of studying and calculating.Success comes from pure luck and no hard work can be a real problem.Imagine she's been picked from nowhere because of her looks.She is going to feel insecure,because she knows she didn't do anything to earn her stardom（演员身份）.On the other hand,think about an actress who's spent years learning and working.When she finally has good luck and becomes a success,she will handle stardom better.She knows she earns it.When it comes to success,I think that hard work and luck go hand in hand.A.Opportunity often depends on luck.B.Luck is also important in people's life.C.Success without some luck is almost impossible.D.Hard work plays a very important part in success.E.However,Columbus' chance discovery wasn't pure luck.F.For example,consider a teenage girl who becomes a movie star.G.People who work hard help make their own luck by being ready when opportunity knocks.