题干
— ________ we clean the classroom immediately?
— No, you ________. You ________ clean it after school.
A：Must; needn't; can
B：Need; mustn't; may
C：Must; mustn't; can
D：Shall; can't; may
答案(点此获取答案解析）
A
cC中，物质的含量A％和C％随温度的变化曲线如图所示，下列说法正确的是（ ）