题干

如图表示根细胞液中三种物质随氧分压变化的曲线,下列说法正确的是(  )

A:都是通过主动运输从土壤中吸收来的

B:浓度变化不会影响到细胞吸水

C:糖的降低与K、N的增加没有关系

D:细胞膜上运输K比运输N的载体多

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答案(点此获取答案解析)

D

同类题1

阅读下面的文字,完成下列小题。

一个多雨的夏天

郭震海

    这似乎是一个多雨的夏天。

    不紧不慢的小雨就像生了根,断断续续下了三天,没有停的迹象。侯东升醒来后,听着外面滴滴答答的雨声,有些烦闷。

    他裹着一条毛巾被,眼睛迷茫地瞪着屋顶。简易的屋顶用横七竖八的施工模型板撑着,上面覆盖着几层黑糊糊的油毡。简易的大宿舍内散发着一股刺鼻的霉味,半碗隔了夜的剩饭放在墙角,已经变质。裸露的砖墙,湿漉漉的,似乎能挤出大把的水来。地上铺着红砖,红砖上撒了薄薄的一层白石灰。十几双黄胶鞋,没有规则地摆放在床铺下。

    “天塌了吧!”一名工友坐起来嘟哝了一句,扑腾一声又躺下了,几根木棍支撑的大床铺发出吱吱呀呀的怪叫。

    “你找死啊!”工友躺下的动作用力过猛,压住了另一位工友的胳膊,后者向他提出强烈的抗议,骂骂咧咧地抽回了胳膊。

    侯东升起身,去床铺头找自己的衣服,想出去走走。他从墙角找出一把破旧的雨伞,走出了工棚。

    外面的雨下大了,一栋高楼起了半截,无数的、长长短短的钢筋头直冲云霄,在雨中显得亮晶晶的,有点刺眼。如果不下雨,这栋起了半截的楼上肯定站满了人。无数顶安全帽,无数双劳作的手。在轰轰隆隆的机械声中,他们完全可以站在高墙上,边劳作边唱信天游。有的工友已经在城里待了十多年,甚至更长时间。他们就像一群特殊的候鸟,每年开春告别妻儿老小,来到城里,冬天又会回到乡村。他们没有走进过KTV,但一步步升高的楼顶上,就是他们的乐场,他们可以怒吼,可以咆哮,可以唱着哭,也可以唱着笑。只要手不闲着,至于嘴,爱干吗就干吗,就是站在墙头上像一个英雄般的去演说,也没有人注意,更没有人管。他们的声音在车水马龙的城市里显得异常微弱,微弱得站在楼下就完全听不到了。

    半夜里,无数盏大灯会将整个工地照亮,高楼一天不封顶,热闹的景象就一天不减,唯有雨能阻断这喧闹的一切。侯东升和大多工友一样,既盼雨,又恨雨。为什么呢?盼雨,是因为下雨了他们可以美美地睡个懒觉,无休止的劳作可以得到短暂休息;恨雨,是因为下雨就意味着他们会没有工,工是什么,就是钱。他们从四面八方拥进这座陌生的城市,就是想多挣点工,年底多拿点钱。

    侯东升撑着伞,不知道该去哪里,更不知道该干什么。路过一座天桥,桥下积满了水,飞驰而来的车辆迅速通过天桥,激起很高的水花。

    “你找死啊!”一个撑着小花伞的女人,被车辆激起的泥水溅了一身,她怒气冲冲地骂道。侯东升突然觉得,城里人说话和他们其实没有区别,就比如这句“找死啊!”他这样说,工友们这样说,城里人也这样说。

    在一个玻璃橱窗前他看到一则大大的广告:“家,温馨的港湾。”城市里到处都是这样的广告。侯东升觉得每一则广告都与他们有关又无关。他们一年四季就像蚂蚁一样在钢筋与水泥的森林中不停地修筑城市里的家,城市在一天天长高变大,而他们没有家,他们的家在乡下。

    侯东升给乡下的妻子打了一个电话,妻子开心地说,真好,庄稼灌浆了,下了一场难得的透雨。侯东升在电话里骂,好个屁。妻子说,你个鞭打的侯东升,你个不要脸的侯东升,你变了,变得不再爱惜庄稼,变得像城里人了,变得……

    我真的变了吗?放下电话,侯东升想,我到底是城里人还是乡下人?他抬头望着灰蒙蒙的天……

同类题4

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