一个有理数与它相反数的积[ ]
A.一定是正数
B.一定是负数
C.一定不大于0
D.一定大于0
答案：C
— Whose ruler is it?
— Maybe it's ____________.[ ]
A. Peter
B. Peters
C. Mary's
D. her
迈克尔逊测光速应用了发散式思维方式
