简述皮亚杰儿童认知发展的阶段理论。
参考答案：感觉运动阶段（0-2岁）前运算阶段（2-7岁）具体运算阶段（7岁-12岁）形式运算阶段（12-15岁）
Why!I have nothing to confess.____you want me to say? [ ]
A. What is it that
B. What it is that
C. How is it that
D. How it is that
生产价格的构成是( )。
A．不变资本
B．可变资本
C．生产成本与平均利润之和
D．全部预付资本
