题干

关于熔化和凝固,下列说法中正确的是

A:固体在熔化时都要吸热,但温度保持不变

B:固体在凝固时都要放热,温度降低

C:固体都有一定的熔点

D:晶体在熔化过程都要吸热,温度保持不变

上一题 下一题 0.0难度 选择题 更新时间:2015-08-12 01:05:17

答案(点此获取答案解析)

D

同类题3

阅读理解

    It's true that “A small change can make a big difference” in our life. A better technical term that can well 1 this idea is the “Butterfly Effect”. A butterfly's 2 wings can make changes in the path of a tornado; it may  3  create or prevent a tornado at a certain location.

    The “Butterfly Effect” plays a role in our  4  to a great extent. Small  5  could make a huge difference in our relationships. Most of the time we take things for granted in our  6 relations. We don't even think of saying “Thank You” to our parents as we  7 they are supposed to do things for us. Understanding some of the subtle(细腻的)feelings of our loved ones and  8 them the way they need would  9 change the relationship into a stronger one. I've come across people who feel  10 in their relationships as they  11 to address these small needs.

    The “Butterfly Effect” also plays a role in our work. Looking  12 into the smallest details while starting a 13 is critical. A subtle mistake while taking care of our customer's  14 could end up creating big trouble at the end of the process. This would mean a huge expense to  15 at the final delivery stage.

    Every morning, the time it takes me to  16 to my office depends on what time I start from my home. It usually takes 30 minutes if I start at 7:20 am. It takes more than a(n)  17 if I start at 7:30 am. At first I was  18 how just a 10-minute difference initially could add more than 30 minutes to the journey.  19 , the number of vehicles that come out on the road increases more than twice due to that 10-minute  20 and it looks like butterflies crowding on the road. Yes, this is nothing but the “Butterfly Effect”.