${\left(2x+5\right)}^5$的展开式中，$x^2$的系数等于40，则${\int }_0^a\left(e^x+2x\right)dx$等于（    ）

作文。
        一个孩子，因为有了期盼，就变成一朵金色花，让妈妈生活得更加温馨；一只丑小鸭，因为有了期盼，就蜕变成一只白天鹅，绽放出生命的美丽；一场春雨，因为有了期盼，就化作春的使者，满怀深情的祝福儿童……
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        ②文体自选（诗歌除外），字数不少于500字；
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根据短文理解，选择正确答案。

    How fit are your teeth? Are you lazy about brushing them? Never fear: An inventor is on the case. An electric toothbrush senses how long and how well you brush, and it lets you track your performance on your phone.

    The Kolibree toothbrush was exhibited at the International Consumer Electronics Show in Las Vegas this week. It senses how it is moved and can send the information to an Android phone or iPhone via a Bluetooth wireless connection.

    The toothbrush will be able to teach you to brush right (don't forget the insides of the teeth!) and make sure you're brushing long enough. “It's kind of like having a doctor actually watch your brushing on a day-to-day basis,” says Thomas Serval, the French inventor.

    The toothbrush will also be able to talk to other applications(应用) on your phone, so developers could, for example, create a game controlled by your toothbrush. You could score points for beating monsters(怪物) among your teeth. “We try to make it smart but also fun,” Serval says.

    Serval says he was inspired by his experience as a father. He would come home from work and ask his kids if they had brushed their teeth. They said “yes,” but Serval would find their toothbrush heads dry. He decided he needed a brush that really told him how well his children brushed.

    The company says the Kolibree will go on sale this summer, for $99 to $199, depending on features. The U.S. is the first target market.

    Serval says that one day, it'll be possible to replace the brush on the handle with a brushing unit that also has a camera. The camera can even examine holes in your teeth while you brush.

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