题干
—________ I clean the classroom now?
—No, you_________.
A：must, mustn't
B：Must, needn't
C：Must, don't have to
D：B and C
答案(点此获取答案解析）
D
—________ I clean the classroom now?
—No, you_________.
A：must, mustn't
B：Must, needn't
C：Must, don't have to
D：B and C
和
，必定存在平面
，使得 （ ）