将硝酸钾的饱和溶液变为不饱和溶液的方法是
---I use your ruler, Lingling? --- Sure. Here you are.
--- Do you like watching TV? ---Yes, I. But only after I finish my homework.
Li Yan is my best friend. She comes a small village.
How is your father? Please say hello to ______ for me.
下列关于实验室制氧气并用排水法收集的实验操作先后顺序中不正确的是()