题目

判断市面上的金首饰是否含有铜,可以取少量样品与某试剂进行反应, 根据现象即可判断, 试剂是（   ） A. 浓盐酸                B. 硝酸              C. 王水               D. 稀硫酸 答案：B 解析:由于金不溶硝酸,但铜可溶于硝酸, 使溶液颜色变蓝, 并可产生红棕色气体, 根据此现象可判断含铜.选词填空（每个词组只能用一次）。10%（1） the board, Sam! Listen carefully!（2）I don’t want to be a nurse when I .（3）I think these books Tom.（4）Tony is very fat because he eats cheese. （5）There are posters in our classroom. Let’s more posters.（6）There are old newspapers. Shall we them ?（7）She is ill(病). You should her.（8）Every weekend Charlie and his wife help people .