搜题请搜索小程序“爱下问搜题”
问题 单项选择题

生态系统对外界干扰具有调节能力才使之保持了相对的稳定，生态系统的这种调节能力 ( )。

A．不是经常变化的
B．不是无限的
C．是无限的
D．不是可预测的

答案

参考答案：B

选择题

下列排列顺序正确的是：

①热稳定性：H2O＞HF＞H2S     ②原子半径：Na＞Mg＞O

③酸性：H3PO4＞H2AsO4＞H2SO4   ④离子半径：O2->F->Mg2+

A．①③

B．②④

C．①④

D．②③
查看答案
单项选择题

Object-oriented analysis （OOA） is a semiformal specification technique for the object-oriented paradigm. Object-oriented analysis consists of three steps. The first step is （） . It determines how the various results are computed by the product and presents this information in the form of a （） and associated scenarios. The second is （） , which determines the classes and their attributes, then determines the interrelationships and interaction among the classes. The last step is （） , which determines the actions performed by or to each class or subclass and presents this information in the form of （）.

The first step is（）.

A．use-case modeling

B．class modeling

C．dynamic modeling

D．behavioral modeling
查看答案