一 ?
— I'm looking for a hat for myself.
A：What are you doing
B：What can I do for you
C：What did you say
丙烷高温裂解生成甲烷和乙烯两种物质．现取丙烷裂解混和物1L充分燃烧后生成相同状况下的二氧化碳为2.25L，则丙烷裂解的百分率是（ ）
