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枯萎的蒲公英

叶子

    ①冬日的午后，阳光虽也明亮，但触一触还是有着沁骨的凉。冬以它的冷漠，裹挟尽百花的艳影，留一地斑驳的枯黄。我不由得竖起大衣的领子。蓦地，一棵蒲公英，出现在我的视野里。

    ②那是一株怎样的蒲公英！叶子的边缘已露出萎黄的老态，但还是透着铁一般的绿。叶们努力地贴向地面，那是一种力量爆发前，手脚触地的姿势。也是呢，霜一次又一次的从天而降，树叶渐渐飞去，草茎慢慢垂下头来。生命的“红灯”，已经在不远处，正一点点逼近自己，那就用尽全部的力，贴向地面，贴向地面……这就是蒲公英最聪明、最刚强也最负责任的举动。他们明白，要想延续久远，就不能把头昂得太高，这样才能把最沉实的爱，尽可能多地传递给儿女。

    ③我的心不由得疼了一下，这像极了我的母亲。

    ④去年的这个时节，冬阳阻不住东奔西跑的北风，正如我阻不住我八十岁老母的脚。她在楼下，为我寻挖着蒲公英。“经霜的婆婆丁（蒲公英的俗号）能消炎败火，你这嗓子，应该吃点。”

    ⑤她半弓着腰，在衰草连片的枯黄里，神情专注地寻找那一小簇一小簇的绿。她时不时地弓腰，用那曾经丰腴饱满而至今肉皮松弛的手，极其小心地翻检着枯黄的草，似乎蒲公英长着脚，一不小心，受了惊吓，就会跑掉了似的。母亲的脚步，已失去了早年的利落，有些蹒跚。那是一双怎样的脚啊！为了让孩子们正常地进入学校，她携夫带子，脚板直探向千里外陌生的异乡；为了一家老小能吃上饭，她不分白天和夜晚，不惧严寒和冰霜，用那细小的绣花针，绣出蟒袍上那呼之欲出的龙的模样，再用一双脚板，驱北风，走冰路，登火车，为一家换回不很丰裕的口粮。

    ⑥风，不时掀起母亲的白发，就像掀动一团绒绒的、洁白的蒲公英的种子。它是想探寻那丝丝缕缕里，藏着多少生活的艰辛？那就去问问太阳和月亮，几十年晨昏的默默相伴，它们如何把一个面如花，发如墨的纤纤女子，变成了眼已花、头覆雪的颤颤老妪！探询那长长短短里，浸着多少爱意的疲累？那就去问问星辰，千千万万次的斗转星移，如何刻录下一个个儿女渐渐长大的足迹，还有母亲的血泪和汗滴。

    ⑦渐次地，她的儿女乘着她那用善良、勤苦织成的爱的伞，找到自己生根发芽的一片片土地。她的脚，不怎么好用了——移动缓慢，脚步蹒跚，但她的心，还是不断地牵挂，就像那天，风在楼下，母亲在楼下。

    ⑧如今，母亲已去，留一棵蒲公英在这冬日里与我面对。我伏下身，看着那泛黄的叶片，眼就情不自禁地盈满了泪。我伸出手指，沿着叶脉轻抚，与你对话。你知道，你知道你碰到了我心最柔软的角落，它在疼吗？在我疼惜的泪光里，我看到你透着如铁的刚强与坚毅，打着爱的“旗语”，温暖着我层层叠叠的孤寂。

    ⑨一阵风吹过，蒲公英的叶子触碰着我的手指，散着阳光融融的暖意，如轻柔的爱抚，久久不去。

（选自《海燕》2015年9期，有删改）

如图所示，轻质木杆AB可以绕O点转动，OA的长度是OB的三倍，A端细线下所挂280N的重物静止在水平地面上，在B点用600N的动力竖直向下拉动，木杆静止不动，则重物对水平地面的压力为____N，此木杆为____（“省力” “费力”“等臂”）杠杆。

如图，将斜边长为4，∠A为30°角的Rt△ABC绕点B顺时针旋转120°得到△A′C′B，弧 $\widehat{AA\text{'}}$ 、 $\widehat{CC\text{'}}$ 是旋转过程中A、C的运动轨迹，则图中阴影部分的面积为（   ）

阅读理解

    Paying a higher price than usual for a ticket to see a film in 3D is the annoyance of many a cinema-goer's life.

    But there may be a benefit to doing so, as a study has found that 3D films exercise the brain and improve short-term functioning in a similar way to brain-training tests.

    The research found that people who watched a movie in 3D improved cognitive (认知) skills, compared to those who watched it in 2D.

    The research was led by neuroscientist(神经学家) Dr Patrick Fagan from Goldsmiths University in London. More than 100 people took part in the experiment, where participants watched Disney film Big Hero 6 in either standard format or RealD 3D.

    They also carried out a brain-training-style test before and after seeing a section from the film. The test covered memory, reaction times and cognitive function and the results were compared later.

    According to the research, which was carried out in partnership with science group Thrill Laboratory, participants experienced a 23 percent increase in cognitive processing, as well as an 11 percent increase in reaction times.

    Dr Fagan said that the results showed enough of an improvement in brain function to suggest that 3D could play a part in improving brain power in the future.

    "These findings are more significant than you might think," he said. "It is a fact that people are living longer and there is a noticeable decline in cognitive brain function in old age which can worsen future quality of life. There has never been a better time to look at ways to improve brain function. The initial results of this study show that 3D films may potentially play a role in slowing this decline."

    A second part of the experiment involved those watching the film being fitted with headsets that scanned brain activity and this too showed heightened (加强的) activity when watching 3D. According to the results, participants were seven percent more engaged with what they were watching, adding to argument that 3D movies are more like watching real-life—something Professor Brendan Walker from Thrill Laboratory agreed with.

    "As Professor Brendan Walker's test concluded, 3D films are more attractive and heighten the senses — this, in turn, makes the brain run at quicker speeds," Dr Fagan said.