RD2型车轴为()吨标准车轴。
A.60
B.50
C.40
参考答案:B
a∈R,且a2+a<0,那么-a,-a3,a2的大小关系是( )
A.a2>-a3>-a
B.-a>a2>-a3
C.-a3>a2>-a
D.a2>-a>-a3
—Whose notebook is this?
—It must be .[ ]
A. Mary
B. Marys
C. Marys'
D. Mary's