题干

对下列事实的解释合理的选项是(   )

选项

事  实

解  释

A

电热水袋中的水加热 后袋子膨胀

袋内水分子增大

B

不宜用凉开水养金鱼

凉开水中不含氧元素

C

电解水时加入少量稀硫酸

是为了增强水的导电性

D

登山时喝空的矿泉水瓶,拧紧瓶盖

下山后瓶子变瘪,瓶内的气体分子体积减小

A:A  

B:B  

C:C  

D:D

上一题 下一题 0.0难度 选择题 更新时间:2017-06-15 03:39:23

答案(点此获取答案解析)

C

同类题2

七选五阅读,根据短文内容,从短文后的选项中选出能填入空白处的最佳选项。选项中有两项多余选项。

Making Peace with Your Parents

    As a teen, you are going through big changes physically and mentally. Your interests are expanding(增加;扩大) ____.

    Here is the challenge: Kids need to explore the world in new ways, and parents need to protect them from the dangers that are all out in that world. These conflicts(冲突)can easily set off fireworks in otherwise calm house. Sometimes conflicts can't be avoided. But by paying attention to the building blocks of successful relationships, you can work towards making home a happy and healthy place for you and your parents.

    For instance, try to find a time to talk when your parents are not angry, tired, distracted , or hungry. A good time to talk is when you are all relaxed. Timing is everything. If the conversation begins to turn into an argument, you'd better calmly and coolly ask to stop the conversation----for now. ____ Listen to what your parents are saying, and repeat it back to them. This shows them that you're listening. ____.

    Respect is the building block of good communication. People who respect each other and care about each other's feelings can disagree without getting things ugly.

     ____How do you build trust? Trust comes by actually doing what you say you're going to do. Some teens find that doing fun activities with their parents can improve their relationships. Sometimes we forget that parents are more than rule-makers----they're interesting people who like to watch movies and go shopping----just like their teenagers!

    What do you do if you are trying your best, but your relationship with your parents continues to be rocky(难以维持的;不稳定的)? ____You can find supportive adults, such as a teacher or a coach, who can lead an ear.

    Remember you can only change your own behavior. Your parents are the only ones who can change theirs.

A. It also gives them a chance to clear things up if you're not on the same page.

B. You can pick it up again when everyone's more relaxed.

C. And then you will be able to accept what your parents say.

D. Faced with the challenge, children don't know what to do.

E. You are more likely to get along with your parents and have more independence if your parents believe in you.

F. And your desire to take control of your own life is growing.

G. You may consider seeking outside help.