氯仿可作为局部麻醉剂，常因保存不慎而被空气中的O₂氧化，产生剧毒的气体-------光气(COCl₂)：2CHCl₃＋O₂→2COCl₂＋2HCl。下列说法正确的是

A．上述反应属于取代反应　　　　　

B．检验氯仿是否变质可选用的试剂是AgNO₃溶液

C．CH₂Cl₂有两种结构，说明CH₄是正四面体结构

D．CHCl₃是常见的有机溶剂，大量使用对环境无影响

小题1:What strange _______________(suggest) you have offered!

小题2: Five         (nine) of the people at the conference come from European countries.

小题3: The house ____________ (it) is not to my mind, but I like its environment.

小题4:My head teacher does everything_______ (patient) while she is in a good mood.

小题5:There are some things that you can’t change, like your       (身高).

小题6:The seats have no back ___________ (紧靠着)which to lean.

小题7:A space sleeping bag is used to be fixed to the walls to prevent_________________(漂浮).

小题8:We must do something to deal with the ____________ (污染) water, otherwise, the fish will die.