—________ 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
—What's her telephone number?
—_______ 0758-0831579.
下列物质的制备,不符合工业生产实际的是( )
商品谷物农业和大牧场放牧业的共同优势及特点是( )