根据上述列车运行时刻表所提供的信息可知：

Z85次列车从北京到苏州所用的时间是____ h，它的平均速度约等于____ km/h．Z85次和Z86次列车的平均速度中____次列车稍大．

    CHICAGO- Have you ever worked on your laptop computer with it sitting on your lap, heating up your legs? If so, you might want to rethink that habit from now on. Doing it a lot can lead to “toasted skin syndrome (症状)”, an unusual-looking spotted skin condition caused by long-term heat exposure (暴露), according to medical reports.

    In one recent case, a 12-year-old boy from California developed a skin discoloration on his left lap after playing computer games a few hours every day for several months. “He recognized that the laptop got hot on the left side; however, he did not change its position,” Swiss researches reported in an article published Monday in the journal Pediatrics.

    Another similar case is a Virginia law student who needed treatment for the spotted darkening on her leg. Dr. Kimberley Salkey, who treated the young woman, learned the student spent about six hours a day working with her computer placed on her lap. As Dr. Salkey later learnt, the temperature under the laptop could reach 51 degrees. That case, from 2007, is one of 10 laptop-related cases reported in medical journals in the past six years.

    The condition can also be caused by overuse of heating pads (垫子) and other heat sources that usually aren't hot enough to cause burns. It's generally harmless but can also cause such permanent (永久的) skin darkening. In very rare cases, it can cause damage leading to skin cancers, said the Swiss researchers, Drs. Andreas Arnold and Peter Itin from University Hospital Basel. They do not mention any skin cancer cases linked to laptop use, but suggest, to be safe, placing a carrying case under the laptop if you have to hold it on your lap.

    Dr. Kimberley Salkey said that under the microscope, the affected skin is similar to skin damaged by long-term sun exposure.

    Major producers including Apple and Dell warn against placing laptops on laps or exposed skin for long periods of time because of the risks for burns. In the past, “toasted skin syndrome” has happened to workers whose jobs require being close to a heat source, including bakers and glass blowers, and in people who gathered near hot stoves to stay warm.

    Dr. Anthony J. Mancini, chief at Children's Memorial Hospital in Chicago, said that it's unlikely that computer use would lead to cancer since it's so easy to avoid close skin contact (接触) with laptops.

在举世瞩目的2008年北京奥运会开幕式上，体操王子──李宁点燃奥运会主火炬。如图所示，他在匀速升空的过程中下列说法正确的是               （    ）

【20世纪的战争与和平】阅读下列材料，回答问题。

材料：美国自从在国联问题上失误之后，孤立主义一度重新甚嚣尘上。在华盛顿体系中，它“参与其中而不负责任”，继而带头提出所谓“非战原则”，甚至在中国东三省发生日本制造的“九一八”事变后，美国国务卿史汀生也只发了个“不承认”的声明，以致法西斯国家得以得寸进尺，终于酿成世界大战。……第二次世界大战爆发后的几年，以往美国之行的政策基本未变，在1935——1937年间接连通过几个“中立法案”，声称要避免“重犯”上次欧战时的错误，禁止向交战国提供贷款、出售军火等。但出于自身利益的考虑，美国在1939年开始修改中立法，取消过时的“军事禁运”，转而实行“现购自运”。当时德国支付和运输能力均较英法为弱，因此这种“现购自运”政策于英法有利。……大约到了1940年，战争形势急转直下，德国先后入侵挪威、丹麦、荷兰、比利时、卢森堡、法国；这年9月27日，日军侵入印度支那，接着又公布日德意三国同盟条约，把矛头指向美国，才使美国在心理上有所觉醒，认识到摆脱孤立主义之必要，包括罗斯福总统本人在内。……正是在这种背景下，美国于1940年9月与英国签订《驱逐舰—海军基地协议》，即由美国向英国提供驱逐舰，英国向美国提供大西洋海军基地；1940年3月签署“租借法案”，决定向反法西斯国家提供援助并拨款70亿美元，以作建立和运输租借物资之用。这样，美国就由中立国变为非交战国，实际上站到了交战的一方。

——摘编自何顺果《美国历史十五讲》

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