观察学习理论的提出者是()
A.奥苏贝尔
B.布鲁纳
C.班杜拉
D.桑代克
参考答案:C
Spring is coming, so _________ your winter coat and _________ your sweater. [ ]
A. put; take off
B. put on; take off
C. take off; put on
狭义的单证是指单据和信用证,广义的单证是指各种文件和凭证。