已知二氯苯的同分异构体有三种,从而可以推知四氯苯的同分异构体数目是( ) A.2种 B.3种 C.4种
目前中国有34个省级行政区,即23个省、5个自治区、4个直辖市、2个特别行政区。我国建立省级行政区制度最早在( ) A.秦朝 B.元
He lives in one room and only eats once a day. He ________ have a lot of money. A. mustn’t B. m
Many years ago in a small German town, a Jewish businessman had the misfortune of owing a large sum of money to the moneylender. The moneylender, who was old and ugly, fancied the businessman’s be
有关燃烧与灭火的说法中错误的是( ) A.用灯帽盖灭酒精灯﹣隔绝空气 B.森林灭火时,建立隔离带﹣隔绝可燃物 C.家具起火,用水扑灭﹣降低温度
(1999年上海,15)实验室进行NaCl溶液蒸发时,一般有以下操作过程:①放置酒精灯 ②固定铁圈位置 ③放上蒸发皿 ④加热搅拌 ⑤停止加热、余热蒸
--Mr. Smith, you are arrested for stealing. Please sign here. --Arrested? Stealing? ________ A. Are you all right? B. You can't be serious! C. I'm a foreigne
下列四组词语没有错别字的一组是 A.涵养 摩洋工 莅临指导 如愿以偿 精诚所至,金石为开 B.版画 名信片