抗肿瘤药环磷酰胺的结构属于
A．乙撑亚胺类
B．氮芥类
C．亚硝基脲类
D．磺酸酯类
E．三氮烯咪唑类
参考答案：B
管理学反映了管理过程的客观规律性，具有显著的科学性。但是，管理过程中的诸多不确定因素使管理本身无法完全量化，故而只是一种不精确的科学。（）
Prototype method is one of the software engineering methods frequently used, which of the following item is the necessary condition for implementing prototype method Ⅰ．Can acquire the user requirement quickly Ⅱ．Have the tools for building software fast Ⅲ．Have a certain accumulation of prototype systems
A． Ⅰ only
B． Ⅰand Ⅱ
C． Ⅱ and Ⅲ
D． all
