假定英语课上老师要求同桌之间交换修改作文，请你修改你同桌写的以下作文。短文中共有10处错误，每句中最多有两处。错误涉及一个单词的增加、删
有一包白色粉末，取少量溶于水，用铂丝蘸取少许溶液，在无色火焰上灼烧，火焰呈黄色，若透过蓝色钴玻璃观看，则呈浅紫色。称取少量粉末加热，
以下是王莉同学学习之余的活动，涉及到化学变化的是（ ） A．用小刀刨削铅笔 B．铅笔写字画画 C．焚烧草稿纸 D．清理打扫灰烬
选择填空 A boy with two dogs_____ when the earthquake rocked the city. A. were sleeping B. is asleep C. was sleeping D. are asleep
If there is _____ emergency, they have to travel three hours to get to ____ nearest hospital for help. A. the; / B. an; the
Dick was driving a large American car. As soon as the race started, he pulled out in front. As the race went on, he kept the first place. And he was far ahead of Wilson, the man in the second place.Wh
张华到雅格尔专卖店去购买了一套标价2000元的西服，货币在履行标价2000元的职能时（ ） Ａ．只需要观念中的货币 Ｂ．必须是现实的货币 Ｃ
是
的两个顶点，且
，则顶点
的轨迹方程是 
；