题干

如图为初中化学常见气体的发生与收集装置.

上一题 下一题 0.0难度 选择题 更新时间:2012-08-30 05:45:24

答案(点此获取答案解析)

同类题3

阅读下文,完成下列各题。

读书与梦想

刘墉

    ①诚品书店邀靖我做校园巡日演讲,我定的讲题是:读书最好,有梦相随。

    ②我太太看到,筻说有问题,因为去掉了中间的标点,好像是读书最好能接着做梦。

    ③我说这有什么错呢?你没见前两天的报纸上才登,美国有个研究,分两组人,一组上午九点钟上课,晚上九点问他们记得多少;另一组则是晚上九点上课,接着各自去睡,第二天早上九点再问他们记得多少。同样相隔十二小时,后者成绩好得多。可见读书要想效果好、记得牢,最好跟着去睡觉。

    ④我这番话,只能供你参考,千万别书本一摆,就去见周公了。

    ⑤但是,我敢说那些有成就的学者,绝不是死读书的。他们很可能像大思想家罗素所说,他想不出怎么写论文,跑出去玩,玩完来就文思泉涌。或像爱因斯坦,在他想通“相对论”的前一天,离开办公室时还对朋友说只怕一辈子都搞不懂了,结果第二天一醒就找到了答案。

    ⑥更实在的例子是发现了苯环分子结构的柯库尔,他不是由梦到一条蛇咬着自己的尾巴,得到了白天百思不解的答案吗?

    ⑦可见书要读,梦也要做;读书是紧,做梦是松。

    ⑧许多年前,老师对我说,青春不要留白。是的,青春短暂,不能白过,但是读书不一样。我们的脑海好像个仓库,不会管理的人,只知把东西堆进去,塞到连转身都不方便;会管理的则知道分门别类,把容易坏的常拿出来检查,不堪用的扔掉。因此,仓库里有条不紊,不但进出货方便,空出来的地方说不定还能摆张乒乓球桌呢!

    ⑨所以,脑仓库的管理一定要留白,只知道博学强记,不断往脑子里塞东西的人,在今天是不容易成功的。

    ⑩如此想想,孔子、柏拉图、亚里斯多德,在他们那个时代,才有几本书好看?汗牛充栋的书简,加起来只怕不过一片光碟的内容。问题是,他们为什么能成为那样伟大的思想家?因为他们既懂得“思而不学则殆”,更懂得“学而不思则罔”。于是在脑海里留下了思考的空间,在读几十本书之后,他们很可能就创作出一本自己的作品,而且超越他读的那几十本书。

    ⑪相对地,却有不计其数的学者,焚膏继晷、皓首穷经,学问塞满一肚子,好像乱堆的仓库,该用的时候找不到,碰到问题不能以所学的解决;说得出一番大道理,却毫无自己的创意。如果把书当成人生旅程的行囊,那些“死书”非但没能帮助他走得远、看得多,反而成为累赘,压得他没见到多少人生的风景。

    ⑫当你发现书已经读死了,记不住了、想不开了,就暂时把书放下,看看外面的绿树蓝天,让思想驰骋,让理想飞扬,想想那书里有多少东西可以给你启发。而且你可以由读这本书,想到读那本书,把相关的东西串起来。这样书才能成为活的,成为你生活的一部分。它不但让你用来应付老师的考卷,更能应付人生的考试。

    ⑬于是。你成为真正的爱书人,书为你实现梦想、打开心窗。

    ⑭所以我说:读书最好,有梦相随!

(选自《再试一次,就成功》,有改动)

同类题4

阅读理解

    Fear may be felt in the heart as well as in the head, according to a study that has found a link between the cycles of a beating heart and the chance of someone feeling fear.

    Tests on healthy volunteers found that they were more likely to feel a sense of fear at the moment when their hearts are contracting(收缩)and pumping blood around their bodies, compared with the point when the heartbeat is relaxed. Scientists say the results suggest that the heart is able to influence how the brain responds to a fearful event, depending on which point it is at in its regular cycle of contraction and relaxation.

    Sarah Garfinkel at the Brighton and Sussex Medical School said: “Our study shows for the first time that the way in which we deal with fear is different depending on when we see fearful pictures in relation to our heart.”

    The study tested 20 healthy volunteers on their reactions to fear as they were shown pictures of fearful faces. Dr Garfinkel said, “The study showed that fearful faces are better noticed when the heart is pumping than when it is relaxed. Thus our hearts can also affect what we see and what we don't see and guide whether we see fear.”

    To further understand this relationship, the scientists also used a brain scanner(扫描仪)to show how the brain influences the way the heart changes a person's feeling of fear.

    “We have found an important mechanism by which the heart and brain ‘speak' to each other to change our feelings and reduce fear,” Dr Garfinkel said.

    “We hope that by increasing our understanding about how fear is dealt with and ways that it could be reduced, we may be able to develop more successful treatments for anxiety disorders, and also for those who may be suffering from serious stress disorder.”