题目

分别给甲、乙两种固态物质加热，最终全部变成液态，它们的温度随加热时间变化的图像如题图所示，下列说法正确的是（ ）A.甲物质是晶体，乙物质是非晶体B.甲物质的熔点为210℃C.乙物质在BC段时处于固液共存状态D.乙物质在BC段温度不变，不吸热 答案：【答案】C【解析】A．甲从一开始就熔化，没有固定的熔化温度，即甲没有熔点，所以甲是非晶体；乙在熔化过程中有温度不变的过程，即乙有一定的熔点，所以乙是晶体；故A错误；B．分析图像可知，甲是非晶体，没有熔点，故B错误；C．因为晶体有一定的熔点，在熔化过程中是固液共存状态，所以乙Hip-pop DancingHip-pop dancing is popular with many young people today.They like it1.they can invent their own moves.They use this dance2.(show) their love for life.It also shows that they feel good about life,that they just want to be3.(they) and enjoy life,and that they are not afraid of problems.Hip-hop dancing has a history of more than 30 years.It first began in the 1980s in the US.In early times,it4. (see) in New York and Los Angeles.At that time,many young black people often danced5.music in the streets. They used their legs,arms,heads and even6.(shoulder) to dance.Many young people still use most of these moves today.Hip-pop dancing7.(become) popular all over the world because of the 1983 movie Flash Dance.Some people performed Hip-hop dancing in8.movie.People enjoyed their performances.They began to dance like them.9. (gradual),it became popular.There are two kinds of Hip-pop dancing: the new school and the old school.More and more young people are learning Hip-pop dancing.People believe that10.is a good way to exercise their bodies,and that it is good for their health.