已知A，B两地相距160km，一辆汽车从A地到B地的速度比原来提高了25%，结果比原来提前0.4h到达，这辆汽车原来的速度是____km/h．

    Many parents have learned the hard way that what sounds like open communication is often the very thing that closes a youngster's ears and mouth. One common mistake is the Lecture, the long monologue that often starts with “When I was your age” Eighteen-year-old Kelly calls lectures “long, one-side discussions in which I don't say much.”

    Kids reflexively(条件反射地)shut down in the face of a lecture. Their eyes glaze over(呆滞),and they don't register any incoming information. Listen to 13-year-old Sarah describe her least favorite times with her mom and dad. “First, they scream. Then comes the ‘We're so disappointed' speech. Then the ‘I never did that to my parents' lecture begins. After that, even if they realize how ridiculous they sound they never take it back.”

    Lines like “When you have children of your own, you'll understand” have been seriously said by parents since time immemorial. But many of our expert parents, like Bobby, a registered nurse and mother of three, feel that by falling back on clichés(陈词滥调)to justify your actions, we weaken our position.

    Since kids are creatures of here and now, the far-off future has no relevance to them. Therefore, good communicators like Bobby suggest, “Give specific reasons for your actions in present language: ‘I'm not letting you go to the party because I don't think there will be enough adult supervisions.'”

    Betty, who lives in Missouri, uses an indirect approach. “I find that warnings are accepted more readily if I discuss a news article on a subject I am concerned about. My husband and I talk about it while our children absorb the information. Then they never think I'm preaching(布道).”

    This really helped when Betty's kids began driving. Instead of constantly repeating “Don't drink; don't speed,” she would talk about articles in the paper and express sympathy for the victims of a car crash. Betty made no special effort to draw her kids into the conversation. She depended on a teenager's strong desire to put in his opinions---especially if he thinks he isn't being asked for them.

阅读下面的文字，完成下面小题。

文星之陨

周汝昌

    乾隆二十四年，因平定西陲，圣上一心要大肆庆贺，命令修茸紫光阁，欲寻觅画师为五十名功臣绘像。人物肖像之外，还有巨幅的战役情景全图、地图若千帧。宫廷御画院人手不够用，江南总督尹继善推荐了雪芹。这样的画是何情形？那是生命精气的巨大消耗，是画好了只有“圣上”一览，而世人永无欣赏之权利与荣幸。学艺一生，难道就为这样一个“结果”？

    “捐躯报国恩，未报身犹存。眼底物多情，君恩或可待。”这是《石头记》中的一首诗，而实在是他对于显责要招他入馆画像的一个回敬词。这种狂傲不拘的答复，不但回绝了君恩，也满可招来杀身之祸。

    乾隆二十七年，是壬午年（1762)。夏秋之际，雪芹的处境又因书稿而引出巨大的变化。《石头记》被判为淫邪之书，一方面他要紧张地“删削”整编出一部应付“进呈（皇帝）”的本子，一方面地方官吏正在向百姓严加逼迫欺凌，以至于拆毁住房，横加驱逐。雪芹一生坎坷，途将穷而日薄暮，而时至此间，竞真如前人所说，奔走无家----及至有家，家复被拆，仅此数椽片瓦，亦难逃毒手。才人之困厄，虽自古史不绝书，然厄至于此极者，亦可称绝矣！拆毁居屋的打击十二分沉重。“删削进呈”的打击更是加倍严峻。拆迁被逐，犹可忍受苦挨，但笔墨心血的摧残破坏，则实在创伤了雪芹的整个身心，他几乎不能负荷精神之压抑迫害。

    壬午这一年，遂成为雪芹生命精神能否支撑延续的关键岁月。

    壬午年的新正，乾隆离京南巡。“圣驾”所到之处，真是千般锦绣，万众繁华，直使老皇上康熙的旧事黯然失色。乾隆还特下御旨，训诫各处官员，其中透露：“各处行宫，靡丽饰观，名山胜迹，凡所经过，悉多加修整；凡地方预备的一切饰具，均须异于凡俗。”于此，可见一斑。而其时各省灾情连续，与南巡的“盛”典，正是相映成“趣”。

    “删削进呈”的事果然发作了。当时，人人皆知道作这部“淫书” “邪书”的人是谁。雪芹为此， 忧愤交加。辛酸之泪，书赖以成；而此时又为书之存亡、人之生死硬洒辛酸之泪水。艰难困顿，百般作计，勉强度过了这个壬午之严冬。但雪芹的身体，由此而日见衰坏。

    连年的天灾，已使粮米百物之价不断上涨。百姓人家，更加日月难度。更奇怪地是连富人家也变穷了，以致于卖男卖女。雪芹想起了一首诗，他见传抄时年方二十，引起了誓欲为女子写传的愿望。 此诗为《鬻女行》，其中几句如下：“菽粟年年责不止，甲第因循变贫子。朝餐未饱曰又晡，夜来不见炊烟起。……男媒女妁争携带，背人却鬻东门外。愿君珍重良家人，看取他年掌上儿!”

    此诗所写，一心欲讽当时的富贵人家，小心日后自己的掌上明珠、千金小姐也会成为被无情役使的卑贱女奴！此诗传为当时名诗人陈石闾所作，足以作为当年“盛世”的侧鉴。雪芹想到自己《石头记》中所写不幸女子，其中也包含着这一种类。而今的“菽粟年年责不止”又甚于十几年前，更不知道天下又有几多女儿正如那诗中之女，同归于一个“薄命司”中。想到这里，自己一人的穷愁，又算什么呢？

    谁知，古语说得不虚：福无双至，祸不单行。一桩史不见书的奇事发生了：痘灾夺取了万家儿女 的性命。从三四月起，直到十月止，北京内外，儿童死于痘灾的数以万计。他最怕的事终于临头了： 惟一的儿子染上了痘疹，不治身亡。

    儿子殇后，雪芹悲痛难以自持，不久也病倒了。乾隆二十八年的除夕，别人家正是香烟爆竹，笑语欢腾的时刻，雪芹在极其凄凉悲惨的情境下离开了人世！

-----摘编自周汝昌《曹雪芹》

相关链接：①孟子：说：“读其书，诵其诗，不知其人，可乎？是以论其世也。”这正是必有一部曹雪芹传的缘由。——周汝昌《曹雪芹》卷头语。

②雪芹名霑，字芹溪，一字芹圃，正白旗汉军。……寅子颓，即雪芹父，亦为江宁织造，故雪芹生于南京——鲁迅《中国小说史略》

近年来，京津冀鲁地区雾霾天气多发的直接原因是（　　）