题干

各种植物的细胞通常具有一定的形态,这主要是因为(  )

A:细胞壁的保护作用

B:细胞壁的支持作用

C:细胞膜的保护作用

D:细胞膜的支持作用

上一题 下一题 0.0难度 选择题 更新时间:2020-03-25 09:45:27

答案(点此获取答案解析)

B

同类题4

阅读文段,完成后面小题

鼓神

王雁

    ①那一年冬天,我流落到陕西省略阳县。这里地处秦岭腹地,山高坡陡民穷,是李白为之嗟吁的蜀道第一关。因为生意亏了本,我流连在这里,贩点山货倒点野味,甚是凄惶可怜,甚至到了春节年关还不敢作归乡的打算。

    ②春节的气氛越来越浓,鞭炮声鼓锣声从街巷小院传来,听得人心烦意乱,无奈中,我裹掖着衣服离开县城走向一个熟悉的小山村。谁知这里也在操练鼓锣作春节上街游行的准备。既然躲不掉就留下来听听吧。于是我就混在一帮老头婆姨姑娘小孩子中间看着坝中十来个中青年汉子把鼓锣敲得震天价响。

    ③敲打锣鼓的汉子们敦实威风,这些平时在山中辛苦刨食的人此时一个个精神抖擞,红光满面,卖着狂傲,逞着威风,显得不可一世。这气氛使我这个异乡人感到更加的凄惶悲哀,孤独孑孑。我准备悄悄地离开。正在这时,敲打大鼓的壮汉把双槌一收,抹一下额上的汗水,用眼光把人群扫了一遍,最后目光定在我身边的一个瘦老头身上,说:“张伯,你来玩一把。”“别,别……”,这个叫张伯的老头既瘦弱又邋遢,穿着一件破旧的黑布棉袄,双手操在袖筒中甚是羞惑地直往后退。我感到他也是像我一样的怕过年的落魄人。但姑娘媳妇们却揪住他往前推搡,说:“鼓神,来一个!”打鼓的汉子一脸虔诚,把有如婴儿手臂粗的双槌直往他面前送,那些打小鼓腰鼓铜锣铜钹的后生们也满脸殷殷地望着他……这倒引起了我的好奇。

    ④可能感到再也推辞不了,张伯突然像运气似的抡了抡手臂,脱袄,仍衣,大步流星,就站稳在了大鼓前。他拉开架势,将双槌高擎过头,布满皱纹和胡茬的脸上突然焕发豪气万丈,一个在黄土中长大的像黄土一般普通的汉子忽然间像天神降临高耸在鼓阵中间;一个在群山中滚爬像山石一样平凡的山民一瞬间如金刚发威挺立在群峰之上。.他的眼睛充满光辉,脸上透出神圣,在轻敲几下鼓沿后,双臂猛一挥,一声石破天惊的巨响倏地刺进了我的耳膜和心脏,接着小鼓铜锣一起轰鸣,一股原始混沌的神秘冲动和古老意念的混乱音符猛地从地底蹿出来通过双脚直抵进了我的心中,使我有了一种脱胎换骨般的剧痛的快感。

    ⑤我像被魔语诅咒了似的,双目紧盯着他,只见他急敲慢叩--急如狂风暴雨,缓似岚岗生月;重擂轻掠——重如万马奔腾,轻似惊鹿踏雪,把一面鼓指派得出神入化。除了力的迸射,还有技的绽放。老人时而槌抹鼓沿,时而肘杵鼓面,时而跃腾猛捶,时而低伏轻抚,柔时如丝绸无骨,刚时像枪挑滑轮;乱则乌云横飞,齐则兵阵突进。铁马兵戈飞鸣镝,细雨轻风荷叶清,劈山开路是男儿,再闻堂前机杼声……

    ⑥轰鸣!呼啸!冲突!纠缠!齐整!狂乱!

    ⑦就在敲击出的声声鼓鸣中,我似乎听到了天庭的意志,大地的精神,男人的cū guǎng _____,女人的娇娉,还有生命,婴儿落地开始的生命,老人撒手西去的生命……这些奇妙的幻象在锣鼓声交织而成的音韵的罗网中不断地冲突,纠缠,呼啸,狂乱……它们似在演绎着生命,似在点拨着生命,似在操纵着人类奔向精神将要达及的终点……

    ⑧我虽然肃立的山民之间,我虽然肃立在山民中间,但精神却是跪着的。形似卑微而神不卑微,处身卑微而心不卑微——调度这阵势,创造这奇迹的老者已不再是一个焉耷汉,而是一个飘逸的精灵!这个人中的英杰此时就代表着人类在立地顶天!我惊愕了,世上竟有着这样的声音,这是一串神秘的符号,一团无形的罡声;我醒悟了,生命中原本就没有卑微和可怜,卑贱者豪迈,低微者挺拔,全在于自己.

    ⑨我从人群中慢慢地退了出来,充满敬意地望着他们。我想我该回家过年了。

同类题5

阅读下面材料,在空白处填入适当的内容(不多于3个单词)或括号内单词的正确形式。

    Many teachers believe that the responsibilities for learning lie with the student. ____ a long reading assignment is given, instructors expect students to be familiar with ____ (inform) in the reading even if they do not discuss it in class or take an examination. The ideal student is considered to be one who is motivated to learn for the sake of learning, not the one interested only in getting high grades. Sometimes homework is returned ____ brief written comments but without a grade. Even if a grade is not given, the student is ____ (responsibility) for learning the material assigned. When research ____ (assign), the professor expects the student to take it actively and to complete it with minimum guidance. It is the student's responsibility to find books, magazines, and articles in the library. Professors do not have the time to explain ____ a university library works; they expect students, ____ (especial) graduate students, to be able to exhaust the reference origins in the library. Professors will help students who need it, but prefer that their students should not be too dependent on them. In the United States, professors have many other duties ____ teaching, such as administrative or research work. Therefore, the time ____ a professor can spend with a student outside of class ____ (limit). If a student has problems with classroom work, the student should either approach a professor during office hours or make an appointment.