题目

下列有关试剂的保存方法，错误的是（） A . 金属钠保存在煤油中 B . 浓硝酸保存在无色细口瓶中 C . 液溴应保存在棕色细口瓶中，并加水液封 D . 漂白粉要密封存放于干燥阴凉处 答案：B此题要求改正所给段文中的错误。对标有题号的每一行作出判断：如无错误，在该行右边横线上画出一个勾（√）；如有错误（每行只有一个错误），则按下列情况改正：        该行多一个词：把多余的词用斜线划掉，在该行右边横线上写出该词，并也用斜线划掉。        该行缺一个词;在缺词处加一个漏字符号（/\）,在该行右边横线上写出该加的词。        该行错一个词：在错的词下划一横线，在该行右边横线上写出改正后的词。 My classmates and I worked as volunteer in Beijing                        1．________ Paralympics in September 13．Early in the morning at 7:20 ,             2．________ we gathered at the National Stadium , namely the Bird’s Nest．        3．________ As soon as we got into it ten minutes late ,we started to do            4．________ some cleaning ．From 9:00 am to 4:00 pm , we tried our best help     5．________ the disabled athletes to get ready for their competitions , leading the      6．________ audience to their seats and keep order ．It was until 12:00 that we    7．________ had lunch and took a rest ,which last about an hour ．We stopped     8．________ working at 4:00．Though it was a tired job , We felt                           9．________ that it an honor to serve the disabled friends from all over the world． 10．________