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实验室制取氧气时,若采用排水法收集气体,可以按照如图所示的各步操作实验:

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同类题1

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养一畦露水

许冬林

       ①露水是下在乡村的。只有古老的山野乡村,才养得活精灵一样的露水。

       ②童年时,在露水里泡大,以为露水是入不得诗文的,直到读《诗经》里的《蒹葭》才开了心窗。“蒹葭苍苍,白露为霜。所谓伊人,在水一方。”古老的风情画呈现于眼前:雾色迷濛,芦苇郁郁葱葱,美丽的女子在露水的清凉气息里如远如近……

       ③我的童年里也有睡在苇叶上的露水,但那是另一种风情。生产队里养着一条褐色水牛,农忙时节,孩子们大清早起来割牛草。我和堂姐相约着,去村西河边的芦苇荡里割草。卷起裤管下去,脚下的软泥滑腻清凉,芦苇一碰,露水珠子簌簌洒一身。从脖子到后脊,到前胸,露水的凉意在皮肤上蔓延,还似乎带着微甜的味道。苇丛里的青草又长又嫩,几刀便可割一大把,有时还顺便割一把细嫩的水芹,算作中饭菜。出了芦苇荡,几个大青草把子拎在手上,一路滴着露水。我们的头发和衣服,也被露水打得湿透。仿佛洗了个露水浴,身上、眉毛上、眼睛里,皆是露水。白露未晞。白露未已。

       ④那时候过暑假,晚上不爱在家里睡觉,而是在平房顶上露宿。堂姐堂哥堂弟,唧唧喳喳的一大群,自带凉席,都来我家的平房顶上睡觉。我们简直成了原始部落,月光为帐,星星为灯,感觉自己就那么睡在天地之间,也像草叶子上的一滴露水。到后半夜,露水重重地下来,裹身的毯子又凉又软,翻个身,贴着堂姐的后背,听她说断断续续的梦话,窃窃想笑。星星在耳边,垂垂欲落,虫声蛙声都已歇了,四下阒寂。满世界,只剩下露水的清凉气息在流散、漫溢。露水里睡着,露水里醒来。清晨下房顶,常看见邻家的瓦楞上结着蛛网,蛛网上也悬挂着露珠,亮晶晶的,在晨风里摇摇欲坠。

       ⑤暑假一过,初秋早晨上学,穿过弯弯曲曲的田埂,也是一路蹚着露水去学校。到学校,一双小脚泡得好白,又白又凉,嫩藕一般,脚丫里有草屑和碎小的野花。那时候,常提着凉鞋上学,到了学校后,才下到学校前的池塘边,洗掉脚上的草屑和野花,将一双被露水洗得格外好看的小脚插进凉鞋里。有时不舍得插:是露水让一个乡下小姑娘拥有了一双不为外人知晓的好看的脚。

       ⑥成年之后,庸庸碌碌,在家和单位之间来回折返,过着千篇一律的两点一线式生活。有一日,读《枕草子》里写露水的几句,才想起自己似乎好多年没看见露水了。忙时只顾着抬头往前赶路,快!快!闲时只想饱饱地睡会儿懒觉,起床时,草木上的露水已经遁形。以至以为:露水,是只下在童年的!

       ⑦当然不是。露水一直在下,下在童年,下在乡村,下在有闲情闲趣的人那里。

       ⑧《枕草子》里写露水的笔墨多而有情趣,最爱玩味的是:“我注意到皇后御前的草长得挺高又茂密,遂建议:‘怎么任它长得这么高呀,不会叫人来芟除吗?’没想到,却听见宰相的声音答说:‘故意留着,让它们沾上露,好让皇后娘娘赏览的。’真有意思。”读到这里,我恍然觉得游离多年的一片小魂儿给招回来了。养花种草,不是目的,是为了给一个闲淡的女人去看清晨的露。烽火戏诸侯,裂帛博取美人笑,都不及人家种草来养露水的风雅。

       ⑨我读着《枕草子》,不觉痴想起来。痴想有一天……

       ⑩养一畦露水,在露水里养一个清凉的自己。生命短暂渺小,唯求澄澈晶莹,无尘无染。让美好持续,一如少年时。

(选自《深圳商报》2013年11月5日  有删改)

同类题4

阅读理解

    One day when I was 12, my mother gave me an order: I was to walk to the public library, and borrow at least one book for the summer. This was one more weapon for her to defeat my strange problem—inability to read.

    In the library, I found my way into the “Children's Room.” I sat down on the floor and pulled a few books off the shelf at random. The cover of a book caught my eye. It presented a picture of a beagle. I had recently had a beagle, the first and only animal companion I ever had as a child. He was my secret sharer, but one morning, he was gone, given away to someone who had the space and the money to care for him. I never forgot my beagle.

    There on the book's cover was a beagle which looked identical (相同的) to my dog. I ran my fingers over the picture of the dog on the cover. My eyes ran across the title, Amos, the Beagle with a Plan. Unknowingly, I had read the title. Without opening the book, I borrowed it from the library for the summer.

    Under the shade of a bush, I started to read about Amos. I read very, very slowly with difficulty. Though pages were turned slowly, I got the main idea of the story about a dog who, like mine, had been separated from his family and who finally found his way back home. The dog was my dog, and I was the little boy in the book. At the end of the story, my mind continued the final scene of reunion, on and on, until my own lost dog and I were, in my mind, running together.

    My mother's call returned me to the real world. I suddenly realized something: I had read a book, and I had loved reading that book. Everyone knew I could not read. But I had read it. Books could be incredibly wonderful and I was going to read them.

    I never told my mother about my “miraculous” (奇迹般的) experience that summer, but she saw a slow but remarkable improvement in my classroom performance during the next year. And years later, she was proud that her son had read thousands of books, was awarded a PhD in literature, and authored his own books, articles, poetry and fiction. The power of the words was held.