动物笼具架和一切用具，包括狗链、猴链接触动物的表面应光滑、（）、无锐利棱角，以防伤害动物。
A.无刺
B.钩状
C.圆弧状
D.湿润
参考答案：A
方程2x2+x+m=0有两个不相等的实数根，则m的取值范围是______．
The prototyping method is a dynamic design processes, which requires people who use prototyping method to have the following capability of （）.
A.proficient program expertise
B.immediately acquire requirement
C.coordinate & organize eloquently
D.handle tools smartly
