It was a Monday morning. When a teacher walked into the1, he heard a low voice: “Here is the teacher. I am 2this boring fellow(烦人的家伙) is going to talk about putting in commas(逗号).” It was a boy's3. His name was Bill. He was talking4the boy next to him. The teacher didn't get angry. He said5about it, then he really began to talk about putting in commas, and then he wrote6the sentence: “Bill says the teacher is a boring fellow.” The class7and Bill's face8red. “Now,” said the teacher, “I'll 9you how important commas are.”

    He put two commas in the sentence, and now read, “10is a boring fellow.”

①W是茶叶，春季茶叶价格上涨

②W是汽车，城市汽车限号限行

③W是纸质书，电子书价格下降

④W是手机，取消国内长途及漫游费

某不纯锌块6.5克，与足量盐酸完全反应放出氢气0.18克，则锌块中含有的杂质可能是（）