在心理学研究中,有计划的严格控制或创设条件去主动延期或改变被试的心理活动,从而进行分析研究的方法叫
A. 观察法
B. 心理测验法。
C. 实验法
D. 个案法
表面粗糙度是一种()几何形状误差,也称为()不平度。
______you return the dictionary to the library immediately, you will be fined.
A. If
B. Until
C. Provided
D. Unless
______difficulties they may come across, they will help one another to get over them.
A. However
B. Whatever
C. Whichever
D. Since