题干

“绿色化学”要求在化工合成过程中,目标产物对反应物的原子利用率达到100%,下列反应类型最符合这一要求的是  

A:取代反应

B:加成反应

C:氧化反应

D:置换反应

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答案(点此获取答案解析)

B

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阅读理解

    I log onto a computer at the doctor's office to say I have arrived and then wait until a voice calls me into the examination room.

    There, a robotic nurse directs me onto a device and then takes my blood pressure. Some time later, in steps the doctor, who is also a robot. He notes down my symptoms and gives me a prescription (处方). I pay for my visit using a credit card machine and return home without having met another human being.

    When I call my dentist's office and actually get a human being on the line, I am thrilled. And when I see the introduction of yet more self-service checkout stations at the grocery store, I feel like shouting, “When it comes to cashiers, make mine human, please!”

    After all, human cashiers sometimes give you a store coupon (优惠券) for items you are buying. Even more than that, real-life cashiers often take an interest in particularly cute children, which can brighten a young mother's day. A cashier may also show compassion (同情) for an elderly person struggling to get that last penny out of her purse.

    What technological device would do any of this? I don't want to go back to the Stone Age, but I'm also worried about a world run by machines. Sometimes when you're chatting with someone, you discover things you need to know. Maybe a receptionist needs prayers said for a sick child. Maybe a salesperson can offer a bit of encouragement to a customer who is feeling tired.

Machines can be efficient and cost-effective and they often get the job done just fine. But they lack an element so important to everyday life.

    Call it the spirit, the soul or the heart. It is something no machine will ever have. It is being human that prompts us to smile at others, which may be what they need at that moment.