若|x|=﹣x，则x是[ ]
A．正数
B．负数
C．负数或零
D．正数或零
答案：C
什么是整式？______，整式中如有分母，分母______（含、不含）字母．
We have some houses. But we need _____ .[ ]
A. more many
B. another many
C. many another
D. many more
