— _____________ are you today?
— I feel much better.[ ]
A. Where
B. What
C. How
答案:C
四个有理数的积是负数,则这四个数中负因数的个数是 [ ]
A.1个
B.3个
C.1个或3个
D.不能确定
什么会使变压器发出异常音响?