题干
My room is a mess, but I __________clean it before I go out tonight. I can do it in the morning.
A：daren't
B：shouldn't
C：needn't
D：mustn't
答案(点此获取答案解析）
C
My room is a mess, but I __________clean it before I go out tonight. I can do it in the morning.
A：daren't
B：shouldn't
C：needn't
D：mustn't
的分布列为 
，则 
（ ）