问题 选择题

某同学用CCl4从碘水中提取碘,下面对此实验的有关操作的描述中,错误的是 (   )

A.碘水和CCl4加入分液漏斗中后,塞上上口部的塞子,用右手压住分液漏斗上口部,左手握住活塞部分,把分液漏斗倒转过来振荡

B.静置,待分液漏斗中液体分层后,先使分液漏斗内外空气相通(准备放出液体)

C.打开分液漏斗的活塞,使下层液体沿承接液体的烧杯内壁慢慢流出

D.最后继续打开活塞,另用容器承接并保存上层液体

答案

答案:D

D错,分液时,上层液由分液漏斗上口倒出,下层液体由分液漏斗下口流出;

阅读理解

Before my first summer vacation at college, my roommate Ted asked me to work with him on his father’s farm in Argentina. The idea of spending two months in Argentina was exciting. But I was afraid of it. I had never been far from New England. What would it be like in a strange country? What about the language? The more I thought about it, the more the idea worried me.

In the end I turned down the invitation. As soon as Ted asked somebody else to go, I began kicking myself. I had turned down something I wanted to do because I was afraid, and had ended up feeling depressed (沮丧的) . That unhappy summer taught me a valuable lesson out of which I developed a rule for myself: do what makes you worried; don’t do what makes you depressed.

At the end of my senior year, I began to think about becoming a writer. But my professor was telling me to aim at teaching. I hesitated (犹豫). The idea of trying to live by writing was a lot scarier than spending a summer in Argentina. Back and forth I went, making my decision, unmaking it. Suddenly I realized that every time I gave up the idea of writing, that downhearted feeling went through me.

Giving up on what I really wanted to do depressed me. Right then I learned another lesson. To avoid that kind of depression meant having to bear a certain amount of worry and concern.

When I first began writing articles, I was frequently required to interview big names. Before each interview I would get anxieties (焦虑) in the mind and my hands would shake. One person I particularly admired was the great composer Duke Ellington. On the stage and on television, he seemed the very model of confidence. Then I learned Ellington still got stage fright and had anxietyattacks. I went on doing those frightening interviews. Then I realized that I was even looking forward to the interviews. What had happened to those anxieties?

Well, in truth, the anxieties were still there, but there were fewer of them. I had benefited from a process of overcoming them. If you put an individual in an anxious situation often enough, he will eventually learn that there isn’t anything to be worried about. This brings me to a conclusion: you’ll never get rid of anxiety by avoiding the things that caused it. The point is that the new, the different, is definitely scary (可怕的). But each time you try something, you learn, and as the learning piles up, the world opens to you.

小题1:What does the phrase “turned down” mean in the second paragraph?

A.To say “No” to his roommate.

B.To say in a low voice.

C.To put away the invitation.

D.To take the invitation.小题2:We can infer from the passage that the writer________.

A.finds it difficult to make decision

B.has found out what causes anxiety

C.was inspired (受启发的) by Duke Ellington’s stage fright

D.no longer feels anxious about new experiences小题3:Which of the following opinions does the writer probably accept?

A.Hesitation leads to depression.

B.Anxiety can be a positive drive.

C.Avoiding anxiety reduces depression.

D.Depression is a signal that one is growing up.

单项选择题