可用作弹簧的钢是（）。
A.20
B.9SiCr
C.60Si2Mn
D.20CrMnMo
参考答案：C
关于（-3）4的正确说法是（ ）
A．-3是底数，4是幂
B．-3是底数，4是指数，-81是幂
C．3是底数，4是指数，81是幂
D．-3是底数，4是指数，81是幂
Last weekend, Linda had a very exciting _____.She went to have fun with her friends in Disneyland.
A. news B. information C. experience
