【单选题】某软件公司开发了一组加密类,在使用这些加密类时欲采用简单工厂模式进行设计,为了减少类的个数,将工厂类和抽象加密类合并,基本UML类图如图所示。以下陈述错误的是( )。
A.
在类图中,Cipher类既充当抽象产品类,又充当工厂类
B.
工厂方法 createCipher()的返回类型为Cipher
C.
工厂方法 createCipher()应定义为静态方法
D.
Cipher类中的 encrypt()方法必须为抽象
【简答题】经济特区,经济技术开发区和经济发达、人均耕地特别少的地区,耕地占用税适用税额可以适当提高,但最高不得超过规定税额的( )。
【单选题】经济特区、经济技术开发区和经济发达、人均耕地特别少的地区,耕地占用税的适用税额可以适当提高,但提高幅度最多不得超过规定税额的一定比例。这一比例是( )。
【单选题】一台稳定运行的他励直流电动机,若负载转矩TL不变,适当降低电枢电压或增大电枢回路电阻,当再次稳定运行时,其电枢电流Ia()
【简答题】完形填空。 How do you spend your summer holidays? Do you have a 1 or stay at home? 2 good use of the summer holidays is very important for students. When I was young, I always spent my holidays 3 the count...
【单选题】Which of the following is NOT one of the disadvantages of a longitudinal research?
A.
The subjects may become irritated at repeated testing.
B.
The participants in the study may not stay in one place for many years.
C.
The behavior. of a subject in the study may be measured continuously for many years.
D.
Social changes may be reflected in the behaviors of the subjects participating in the study.
【判断题】三章二节 P77 L仓库平面面积主要是由储存货物数量确定。
【单选题】他励直流电动机在所带负载不变的情况下稳定运行,若此时增大电枢电路的电阻,待重新稳定运行时,电枢电流和转矩将()。
【简答题】Air Pollution When the air is dirty it has become polluted. Air pollution is made up of gases, dust, odors, particles, smoke, fumes, and other substances which can be harmful to humans, animals, plant...
【单选题】他励直流电动机在所带负载不变的情况下稳定运行。若此时增大电枢电路的电阻,待重新稳定运行时,电枢电流和电磁转矩()。