活性污泥中菌胶团的作用是什么？
参考答案：使活性污泥形成絮凝体；使活性污泥易于沉降，达到泥水分离的目的；保护细菌本身不被原生动物吃掉。
补全对话
A : Excuse me! 1
B:I'm from England. 2
A :I am from Canada. I live in Ottawa.
B : Ottawa is a good place. 3
A :I speak English and a little French.
B: 4
A: My favourite sport is basketball. Because I want to play it as well as Yao Ming. 5
B: No,I don't like it.My favourite sport is football.
国家对媒介的管理
