关于摩擦起电和感应起电，以下说法正确的是（   ）

若分式$\frac{x-1}{x+2}$的值为0．则x____ ．

阅读下文，完成下面题目。

为自己减刑

        ①一位朋友几年前进了监狱。有一次我应邀到监狱为犯人们演讲，没有见到他，就请监狱长带给他一张纸条，上面写了一句话：“平日都忙，你现在终于获得了学好一门外语的上好机会。”
        ②几年后我接到一个兴高采烈的电话：“嘿，我出来了！”我一听是他，便问：“外语学好了吗?”他说：“我带出来一部六十万字的译稿，准备出版。”
        ③他是刑满释放的，但我相信他是为自己大大地减了刑。茨威格在《象棋的故事》里写一个被囚禁的人无所事事时度日如年，而获得一本棋谱后日子过得飞快。外语就是我这位朋友的棋谱，轻松愉快得几乎把他的牢狱之灾全然赦免。
        ④真正进监狱的人毕竟不多，但我却由此想到，很多人正恰与我的这位朋友相反，明明没有进监狱却把自己关在心造的监狱里，不肯自我减刑、自我赦免。
        ⑤我见到过一位年轻的公共汽车售票员，一眼就可以看出他非常不喜欢这个职业，懒洋洋地招呼，爱理不理地售票，时不时抬手看着手表，然后满目无聊地看着窗外。我想这辆公共汽车就是他的监狱，他却不知刑期是多久。其实他何不转身把售票当作棋谱和外语呢，满心欢喜地把自己释放出来。
        ⑥对有的人来说，一个仇人也是一座监狱，那人的一举一动都成了层层铁窗，天天为之而郁闷忿恨、担惊受怕。有人干脆扩而大之，把自己的嫉妒对象也当作了监狱。人家的每项成果都成了自己无法忍受的刑罚，白天黑夜独自煎熬。
        ⑦听说过去英国人在印度农村抓贼时方法十分简单，抓到一个窃贼便在地上画一个圈让他呆在里边，抓够了数便把他们一个个从圆圈里拉出来排队押走。这真对得上“画地为牢”这个中国成语了，而我确实相信，世界上最恐怖的监狱并没有铁窗和围墙。
        ⑧人类的智慧可以在不自由中寻找自由，也可以在自由中设置不自由。环顾四周多少匆忙的行人，眉眼带着一座座监狱在奔走。老友长谈，苦叹一声，依稀有锒铛之音在叹息声中盘旋。
        ⑨舒一舒眉，为自己减刑吧。除了自己，还有谁能让你恢复自由?
                                                                                                                                                      选自余秋雨的散文集《文化苦旅》

    Several days ago, Brenda had a car accident that led to one of her legs being cut off. Since then she didn't talk to anyone.

     “I wish I could bring her friends to visit her,” said Brenda's mother. “But it's a long bus trip.” The nurse smiled, “Don't worry. We have a plan.”

    Later that day, the nurse had taken Brenda to another room. “Here's your new roommate, Annie Wiggle-Do,” the nurse introduced a dark-hair teenager on the other bed.

    As soon as the nurse left, she jumped out of her bed with her only foot and sat at the other end of Brenda's bed, “I lost my leg from bone cancer,” she said. “What happened to yours?” Brenda was so shocked that she couldn't say a word. “You're lucky.” Annie continued. “You've still got your knee. They had to take mine.”

     “I'd like to have a chat with you, but my friends are coming any time now, so I have to get ready.” Annie said when she took off her hair! Her head was completely bald(秃头的).

     “Oh, I forgot to tell you, the medicine they gave me to kill the cancer also killed my hair.” Annie looked out her wigs(假发), brown and yellow, short and long, straight and curly.

     “That's why I thought up ‘Annie Wiggle-Do'.” Annie smiled. “Get it? Any wig will do? Annie Wiggle-Do?” “When Annie's friends came, she introduced Brenda to them all. Before long, Brenda started chatting with Annie and her friends. They didn't make her feel like a strange person at all!

    The girls shared their names with each other. When it was time to go to bed, Brenda said, “Good night, Annie-Wiggle-Do. Can't wait till morning.”