下列根据实验操作和现象所得出的结论正确的是( )
选项
实验操作和现象
结论
A
向FeBr2溶液中通入适量Cl2,溶液由浅绿色变为黄色
Cl2氧化性强于Br2
B
常温下,等体积pH=3的HA和HB两种酸分别加水稀释,溶液导电能力如图
HA酸性比HB弱
C
向无水乙醇中加入浓H2SO4,加热,将产生的气体通入酸性KMnO4溶液,紫红色褪去
反应产生乙烯
D
取久置的Na2O2粉末,向其中滴加过量的盐酸,产生无色气体
气体为氧气
A:A
B:B
C:C
D:D
阅读对话,判断正误。
(Sarah is asking a policeman for help. )
Sarah: Excuse me. Where is the Zhongbai Supermarket, please?
Policeman: It's next to the hospital over there.
Sarah: Is it far from here?
Policeman: No.
Sarah: How can I get there?
Policeman: You can walk there.
Sarah: Thank you.
Policeman: You're welcome.
下列各组函数是同一函数的是 ( )①fx=-2x3与gx=x-2x;②fx=x与gx=x2;③fx=x0与gx=1x0;④fx=x2-2x-1与gt=t2-2t-1。
连词成句,注意大、小写及标点符号