已知一合成塔装填有17.2m3触媒，气流量为125000Nm3/h，则其空速为（）。

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 (71) . It determines how the various results are computed by the product and presents this information in the form of a (72) and associated scenarios. The second is (73) , which determines the classes and their attributes, then determines the interrelationships and interaction among the classes. The last step is (74) , which determines the actions performed by or to each class or subclass and presents this information in the form of (75) .

（74）处填（）。

A．static modeling

B．use-case modeling

C．dynamic modeling

D．class modeling

凸缘联轴器属于固定式刚性联轴器。

关于流行性腮腺炎的实验室检查，下列哪项是正确的（）

A.外周血中白细胞计数明显增加

B.血、尿淀粉酶轻至中度增高

C.脑脊液中不能检出病毒

D.早期即可见IgG抗体增高

E.须常规分离病毒以诊断此病

由于与口服降糖药发生相互作用而使降血糖作用减弱的药是（）

A．磺胺类

B．水杨酸类

C．噻嗪类

D．贝特类

E．香豆素类

生产性公司的注册资金应不得少于（）万元。

A.10

B.20

C.40

D.50