底稿的分工与合并导出的底稿的后缀格式是（）
A.sjc
B.sjg
C.sjt
D.bak
参考答案：C
The boy has been _____ his parents for years because they are both disabled. [ ]
A. taking after
B. taking pride in
C. taking care of
D. taking an interest in
导致市场机制和企业的交易费用不同的主要因素在于( )。
A．生产规模的大小 B．信息的不完全性C．契约的完整性 D．经营者的素质
