______ you stepped into the lab with your shoes on? You're supposed to take them off before you enter it.

【正确答案】 A

【答案解析】 how come“怎么”；how dare“怎敢”；how about“怎么样”；how long“多久”。句意：怎么穿着鞋进了实验室?进来之前你该把鞋脱掉。