题干

有一种葡萄:从树上摘下后不保鲜最多只能存放一周,如果放在冷藏室,可以延长保鲜时间,但每天仍有一定数量的葡萄变质,假设保鲜期内的重量基本保持不变,现有一位个体户,按市场价收购了这种葡萄200千克放在冷藏室内,此时市场价为每千克2元,据测算,此后每千克鲜葡萄的市场价格每天可以上涨0.2元,但是,存放一天需各种费用20元,平均每天还有1千克葡萄变质丢弃.
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同类题1

根据短文理解,选择正确答案。

    LONDON—Terror struck in the heart of London on Thursday as explosions ripped through three subway trains and blasted(炸开)the roof off a crowded red double-decker bus. At least 37 people were killed and more than 700 wounded in the deadliest attack on the city since the blitz(闪电战)in World War II.

    British Prime Minister Tony Blair blamed Islamic extremists and said the bombings were designed to coincide with the opening in Scotland of a G-8 summit of the world's most powerful leaders. Foreign Secretary Jack Straw said the bombings—which came the day after London won the bid to host the 2012 Olympics--- have the “hallmarks(特点)of an al-Qaida-related attack”.

    Trapped passengers in the Underground railway threw themselves on the floor, some sobbing. As subway cars quickly filled with smoke, people used their umbrellas try to break the windows so that they could get air. Passengers emerged from the Underground covered with blood and soot(黑烟). On the street, in a light rain, buses ferried the wounded, and doctors used a hotel as a hospital.

     “I didn't hear anything, just a flash of light, people screaming, no thoughts of what it was. I just had to get out of the train,” said subway passenger Chris Randall, 28, who was hospitalized with cuts and burns to the face, the legs and hands.

     “It was chaos(混乱),” said Gary Lewis, 32, evacuated(撤离)from a subway train at King's Cross station. “The one haunting(萦绕)image was someone whose face was totally black( with soot) and pouring with blood.”

    Police said there had been no warning and that the blasts at three subway stations went off within 26 minutes, starting at 8:51 a.m. in an Underground train just outside the financial district. Authorities initially blames a power failure but realized it was a terror attack after the bus bombing near the British Museum at 9:47 a.m.—less than an hour after the first explosion.

同类题4

阅读下面的文字,完成后面小题。

好沉的一抔土

石英

    ①在这里,旧的皇历是更不是了。

    ②原本我以为,黄河口的土是粗糙的、贫瘠的。因为在我幼小时,大人们就告诉我:那是个盐碱沙荒、十年九不收的地方。

    ③但当我实地来到这黄河入海处,亲眼领略了它的豪迈气势和不凡的资质后,我便意外地发现:这里不仅地阔,而且土肥,攥在手里,酥细得像润了油,却又不腻而匀和;凑近鼻沟下一闻,别有一种清香。以我年轻时在老家从事农桑的经验,这样的土质,任管种蔬菜还是种庄稼都是很理想的。

    ④果然,在后首那块干松的地段,好一片秋禾!风过时,高粱擎起硕大的锣鼓槌相互撞击,没有敲出多大的声响,却惊起一对翠蓝色的珍鸟从深处腾出,在半空里飞旋两遭,没有树枝可依,又飘落在旁边的一片谷地,立在穗上颤颤悠悠,像一双新婚伉俪相对荡着秋千。那千支万条谷穗的金笔,在漫野里尽情描绘秋熟的图景。

    ⑤再往前,更接近河口的一片土地,许是刚冲积成不久,还没有好好利用。如此潮润的沃土,瞅着都会口舌生津,谅也不会长时被闲置的。

    ⑥我是个庄户底儿,颇有些“爱土成性”,走着走着,禁不住又珍惜地捧起一抔土来,觉得好沉重,真的——比一般的土要有分量。“你的手感不一样吧?”我们的老向导、四十年的治黄专家王总工程师看出来了,接着他以充满诗意的幽默口吻向我解释,“这土确实有点特殊:黄河口虽说在山东,这里的泥沙却不全姓鲁,它们有的姓甘,有的姓秦,有的姓晋,有的姓豫,大都是外来户。你手里攥着九个省区呢,怎能不重?”

    ⑦我始而以为他是在开玩笑,再一琢磨,或许还真有道理,但究竟是科学上的依据,还是哲理上的深远含义?科学上的道理,土质的某种特殊性,还有待请教;引我深思的倒是他所说的“攥着九个省区”这句话,确实是够有分量的,其中不但有地理上的广阔,更有历史的重负,大河不舍昼夜滔滔奔流,融雪纳雨,诸种情味,羼和着千年万载艰辛的汗珠。经过漫长历史淘滤,轻浮的、劣质的分子被冲出河口,混杂于海水中;能够落下来的便执著地痴恋于河口,不肯随波逐流。这些分子多是精华,它们当然最凝重。

    ⑧这土,攥在手里是无声的,我却觉得它储留、凝结着我们这个民族苦难和奋起的回声。太遥远的且不说,七十多年前,就有黄泛区百姓流离失所啼饥号寒的哭泣,更有1947年6月30日刘邓大军强渡黄河的雄浑声浪……

    ⑨我更深深感悟到:我手里攥着的不是一抔普通的土,一时竟合不得扔弃它——它值得我珍惜并作为一种精神的动力。这时我不仅觉得它的分量沉重,而且攥得好苦!

    ⑩但不论是何种滋味,过去的毕竟已成为过去。现在,我闻到的是风赠秋熟的醇香;眼前,是驰向海口的两栖机动勘测船。王总兴致勃勃地向我透露:三年以内就将结束这里“有水无航,有油无厂,有口无港”的局面。“到那时,你再来看!”

    ⑪他的语气是那么坚定,那么充满信心;不需怀疑,他过去四十年间的治黄成绩就是金质“信用卡”。

    ⑫至此,我可以愉快地松开手了。土,被攥成紧紧的一团,我随手把它揉碎,轻松地撒开去,土星儿均匀地铺在地面上,幻觉中,我的眼前仿佛展开了一幅新洲远景图……

(略有删改)