甲乙两列客车从两地同时相对出发，6小时后在距中点30千米处相遇，慢车每小时行60

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 determine 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．use-case modeling

B．Glass modeling

C．dynamic modeling

D．behavioral modeling

很多人在消费图书、光盘、婚纱这类商品时会采用租赁的方式。这主要是因为此类商品（   ）

A．替代品较少

B．使用次数有限

C．一次性支付困难

D．需求弹性较小

钟面上的时钟在5点敲5下，用时8秒，那么10点时敲了10下，几秒钟敲完？

诊断肺心病的主要依据是（）。

A.长期肺结核病

B.长期慢性支气管炎

C.肺动脉高压及右心室肥大

D.肺动脉狭窄

E.两下肢水肿