题干

水是我们日常生活必不可少的物质,下列有关水的说法正确的是(  )

A:水通电分解时产生的氢气和氧气质量比为2:1

B:活性炭吸附水中的色素和异味是化学变化

C:可用肥皂水区分硬水和软水

D:用过滤的方法可以使硬水软化

上一题 下一题 0.0难度 选择题 更新时间:2018-11-06 06:08:50

答案(点此获取答案解析)

C

同类题4

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。选项中有两项为多余选项。

    Lots of people give you advice on overcoming fear. ____ However, I want to tell you that a world without fear would be more dangerous, less rewarding. So we want to treat fear as a friend? Here are three reasons.

    ____ Think about it. Do you get more nervous when you meet the girl (or guy) of your dreams? Which is more fearful, talking to the boss of your company or to some of your friends? ____ If you didn't have fear to guide you, you might not know that! Not so bad, right?

    Next, fear encourages us to take action. Fear is a call to action. In the past, our ancestors didn't run away in fear when they saw a tiger running toward them but tried to kill it for food. Now, most of us don't face serious danger like hungry tigers every day, but we do face serious bosses or public speaking. So, what can we do? ____

    Lastly, fear lets you know you are alive. Why do we like roller coasters? ____ Same for horror movies.

    So fear can guide you towards what's important for you and encourage you to take action to improve. Don't we all need that kind of friend?

A. The first is that fear is an excellent guide to opportunity.

B. They frighten us in a mostly safe way.

C. Imagine what life would be like without fear.

D. Let fear provide us with the energy to do what needs to be done.

E. Fear is showing you what is important and what matters to you.

F. Don't fear to be wrong.

G. They say if you can overcome fear, you will be successful.