操作和现象
结论
A
向装有Fe(NO3)2溶液的试管中加入稀H2SO4,在管口观察到红棕色气体
HNO3分解生成了NO2
B
向淀粉溶液中加入稀H2SO4,加热几分钟,冷却后再加入新制Cu(OH)2浊液,加热,没有红色沉淀生成
淀粉没有水解成葡萄糖
C
向饱和Na2CO3溶液中通入足量CO2,溶液变浑浊
析出了NaHCO3
D
向无水乙醇中加入浓H2SO4,加热至170℃产生的气体通入酸性KMnO4溶液,红色褪去
使溶液褪色的气体是乙烯
A:A
B:B
C:C
D:D
完成句子(1)I saw the sharks. (改为一般疑问句)____ see the sharks?(2)Were there any famous singers at the aquarium?(否定回答)No, ____ .(3)He did his homework last night.(改为否定句)He ____ his homework last night.(4)The students watched a movie about dolphins at the aquarium. (对划线部分提问)____ the students watch a movie about dolphins?(5)No one came to the sale because the weather was bad. (对划线部分提问)____ no one come to the sale?
结合语境,根据汉语或首字母提示用单词的适当形式填空。