题干

小科在碳酸钠的溶液中滴加氯化钙溶液,产生白色沉淀,然后再滴入适量经过稀释的硫酸溶液,在该实验过程的操作如图所示,下列有关操作与目的分析均正确的是(    )

A:甲中试剂瓶标签正对手心,是为了防止手被腐蚀

B:乙中将滴管伸入试管内,是为了防止试剂滴落到试管外

C:丁中试剂瓶盖倒放在桌面上,主要是为了避免瓶中试剂受污染

D:戊中将水缓慢倒入浓硫酸并搅拌,是为了防止局部过热引起酸液飞溅

上一题 下一题 0.0难度 选择题 更新时间:2019-10-21 09:24:39

答案(点此获取答案解析)

C

同类题2

请阅读下面短文,再短文后表格中的空白处填上适当的单词

Title: Inner voice helps a lot throughout our lives.

    When you couldn't open your mouth till the first two years on the earth, inner voice helps you understand things. Inner voice always shows thoughts and ideas in the body.

    It justifies(判断) what is right and what is wrong. When we go against inner voice, we usually feel uncomfortable throughout our lives.

Sometimes when we are feeling sad, we seem to need some kind of support in spirit. We usually speak to our closest friend or our dearest family member during times of unhappiness to feel better. After talking to them, we suddenly feel active again, because our inner voice reminds us to get on with things and leave the things of the past in the memory.

    Inner voice is always right most of the time, because it knows us better than others and even ourselves. It's good to go by inner voice most of the time. Whenever you are trying to smoke, or whenever you are asked to choose one side in an argument, you are always worried about the result. During these times, your inner voice tells you what to do. If you don't follow your inner voice, you might be unhappy in the future. It's our own choice to either pay no attention to our inner voice or follow it and search for real happiness.

Title: Inner voice helps a lot throughout our lives.

Passage outline

Supporting details

Introduction to inner voice

Before we can talk, inner voice____ understand things, and shows thoughts and ideas in the body.

Things that inner voice helps us with

Inner voice tells us what is right and what is wrong. We usually have an uncomfortable ____ ­throughout our lives when we go against inner voice.

Inner voice reminds us to get on with things and leave the things of the past.

____ why we should go by inner voice

It knows us better than others and even ourselves.

It tells us ____ to do when we are always worried about the result of our choice.

We might be unhappy in the future without ____­our inner voice.