【甲】

    ①自三峡七百里中，两岸连山，略无阙处。重岩叠嶂，隐天蔽日，自非亭午夜分，不见曦月。

    ②至于夏水襄陵，沿溯阻绝。或王命急宣，有时朝发白帝，暮到江陵，其间千二百里，虽乘奔御风，不以疾也。

    ③春冬之时，则素湍绿潭，回清倒影。绝山献多生怪柏，悬泉瀑布，飞漱其间，清荣峻茂，良多趣味。

    ④每至晴初霜旦，林寒涧肃，常有高猿长啸，属引凄异，空谷传响，哀转久绝。故渔者歌曰：“巴东三峡巫峡长，猿鸣三声泪沾裳！”

（《三峡》）

【乙】

    ①崇祯五年十二月，余住西湖。大雪三日，湖中人鸟声俱绝。

    ②是日更定，余拏一小舟，拥毳衣炉火，独往湖心亭看雪。雾凇沆砀，天与云与山与水，上下一白。湖上影子，惟长堤一痕，湖心亭一点，与余舟一芥，舟中人两三粒而已。

（《湖心亭看雪》）

若 a 与 b 互为倒数，那么 a² 与 b² 是否互为倒数？

    The first robots were invented in the1920s. Since then robots ____ (appear) in many American films. In some films, they are stronger, faster and cleverer ____ people.

    In real life, robots are ____ (main) used in factories. They do some dangerous and difficult jobs for humans.

    Robots also help disabled(残疾的) people, for example, blind people. Today many blind people have a guide dog ____ (help) them. In the future, guide dogs might be robot dog.

    One kind of robot guide dog has ____ (wheel). It moves in front of the owner. It is very clever. It knows the speed of its owner's walk. The owner ____ (wear) a special belt(带子). This belt sends instructions ____ the owner from the dog, such as "Stop here", "Turn left" or "Turn right".

    In the United States, another kind of robot helps disabled people to take care of ____ (them) in their daily life. The robot hears the sound of its owner's voice. It follows instructions such as "Turn the page" or "Make a cup of coffee".

    Robots are also used in American hospitals. They can do simple jobs. At one hospital, for example, a robot takes meals from the kitchen to patient's rooms. It ____ gets lost because this robot has a map of the hospital in its computer memory.

     ____ robots can help people in many ways, they will never take the place of humans.