用算式表示下面题中的数量关系．

一辆汽车2小时可以行驶100千米，平均每小时可以行驶多少千米？

阅读理解

    We already know the fastest, least expensive way to slow climate change: Use less energy. With a little effort, and not much money, most of us could reduce our energy diets by 25 percent or more—doing the Earth a favor while also helping our wallets.

    Not long ago, my wife, PJ, and I tried a new diet—not to lose a little weight but to answer an annoying question about climate change. Scientists have reported recently that the world is bending up even faster than predicted only a few years ago, and that the consequences could be severe if we don't keep reducing emissions(排放) of carbon dioxide (CO₂ ) and other greenhouse gases that are trapping heat in our atmosphere.

    We decided to try an experiment. For one month we recorded our personal emissions of CO₂. We wanted to see how much we could cut back, so we went on a strict diet. The average US household(家庭) produces about 150 pounds of CO₂  a day by doing common-place things like turning on air-conditioning or driving cars. That's more than twice the European average and almost five times the global average, mostly because Americans drive more and have bigger houses. But how much should we try to reduce?

    For an answer, I checked with Tim Flannery, author of The Weather Makers: How Man is Changing the Climate and What it Means for Life on Earth. In his book, he had challenged readers to make deep cuts in personal emissions to keep the world from reaching extremely important tipping points, such as the melting(融化) of the ice sheets in Greenland or West Antarctica. "To stay below that point, we need to reduce CO₂  emissions by 80 percent," he said.

    Good advice, I thought. I'd opened our bedroom windows to let in the wind. We'd gotten so used to keeping our air-conditioning going around the clock. I'd almost forgotten the windows even opened. We should not let this happen again. It's time for us to change our habits if necessary.

若点A(2,m)在x轴上，则点B(m-1,m+1)在 （    ）

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                                                                                                          又到麦浪翻滚时

                                                                                                                      周霞

    ①蜗居小城，终日上班下班，做饭吃饭，庸庸常常，忙忙碌碌。傍晚，出去散步，信步走远了些，不知不觉就远离了车马人喧，走上了一条土路。走着走着，田野里就有一阵阵植物的气息飘荡过来，那是甲麦子的昧道。暮色里，一片金黄的暖色蓦然吸引了我。只不过是一小片麦地，却在一瞬间让我的记忆弥漫开来，一直弥漫到老家那翻滚着的无边麦浪里。

    ②我的老家在鲁西北平原。每到这个时节，一望无垠的金色麦浪随风起伏，煞是壮观，乡亲们的脸上也荡漾起富足的笑意。然而，我小时候，抢收麦子却是很辛苦的活儿，早了不好，晚了麦粒就容易掉进地里。那时收割没有机械化，完全要用镰刀一把一把割下来，再一捆捆系紧，运回场院，翻晒碾压，或用脱粒机脱出麦粒，再晒干贮藏。不管天多热，不管人多累，都要马不停蹄地劳作，就担心会遇到雷雨天气。

    ③小时候，麦子成熟前，我们总爱搓麦粒吃。我会先找几颗大麦粒，揉碎在手心，两手相对，槎来搓去，于是一种幸福和喜悦的味道就从手里慢慢弥散开来。搓好了，就张开两手，轻轻一吹，那些皮儿就四散开去，往嘴里一捂，清淡的麦香就从舌尖传递到全身，于是，满心就都是乙麦子的味道。等麦收结束了，我们小孩子就挎上小篮子，到麦地里拾麦穗。拾得多了，父亲会夸我，母亲会把麦穗晒起来，搓成粒，然后用麦子换挂面。母亲做的挂面汤，只是滴几滴香油，倒点香醋，就很好喝。

    ④印象最深的是在一个月光皎洁的晚上，我们全家收割麦子，虽然天色暗了些，也有露水，但不用受曝晒之苦。那时的我还不懂稼穑的辛苦，休息时，还有闲情望望皓月，和家人不停地说笑着，觉得是一种乐事。割麦子时，要是谁被落下了太远，前面的人就会接趟子。这样，有人帮忙，割得慢的人也就有了信心，等到都割完长长的一垄，全家人再齐头并进。累了，就直起腰，抹抹汗，甩甩手，再埋头继续干。天气再热也要穿长袖衣裳，不然，尖尖的麦芒会扎得生疼。脚上穿着母亲在灯下一针一线纳的千层底，倒是不再怕麦茬刺破脚。

    ⑤麦收时节是一年里很累人的时候，又没有工夫去集市买东西，父母总是提前把鸡蛋腌制好，偶尔也会拿出春天里储存的香椿芽。当疲惫地回到家，大家就齐动手，烧火，擀面条，切菜。天热，面条煮好后，要放进刚挑来的井水里浸泡一下，再捞出，这样吃起来才过瘾。这个时节的菜，只有黄瓜、西红柿和菜豆，反正地里长什么就吃什么，吃饱了，好好睡个午觉，再切开一个大西瓜，美美地吃一顿，舒坦极了。太阳稍稍收威，就又起身下地了，麦收不等人呢。

    ⑥麦收时节，大人们总是让自家的娃们去帮老师割麦子。于是，我和伙伴们就组织起来，在麦田里穿梭。师生你追我赶，割得快的学生会善意地取笑一下比他们大不了几岁的老师。不到半天时间，几亩地就割完了。今年春节，和儿时的伙伴通电话，说起当年每到开镰时麦地里弥散着的丙麦子的味道，觉得是那样美好。是呀，那时真好，那时的麦子好，那时的空气也好，那时的师生关系也和谐自然。偶尔的田间劳作，给了我们美好的回忆。

    ⑦那时的感情是那么纯朴，那么温馨，亲切而悠远，令我至今难忘。于是，我拨通了老家的电话，想从乡音里捕捉丁麦子的味道。（有删改）