电压贬值的额定防护有四个等级：CAT（种类）Ⅰ、CATⅡ、CATⅢ、CATⅣ，其中（）直接连接到配电设备的大型用电设备（固定设备）的一次线路及配电设备到插座之间的电力线路

A．CATⅢ

B．CATⅡ

C．CATⅠ

D．CATⅣ

A.CATⅢ

B.CATⅡ

C.CATⅠ

D.CATⅣ

A、A.Cat cat = (Cat)new Animal();

B、B.Animal a = new Cat(); Cat cat = (Cat) a;

C、C.Animal animal = new Cat();

D、D.Animal a = new Dog(); Cat cat = (Cat) a;

有以下类定义,运行后 abstract class Animal{ abstract void say(); } public class Cat extends Animal{ public Cat(){ System.out.printf("I am a cat"); } public static void main(String[] args) { Cat cat=new Cat(); } }

A、I am a cat

B、Animal能编译，Cat不能编译

C、Animal不能编译，Cat能编译

D、编译能通过，但是没有输出结果

A．CAT C13

B．CAT C15

C．CAT C18

D．CAT 3126B

The author wants to write ______.

A．a clog book

B．a cat book

C．a dog and cat book

D．a dog and a cat book

What conditions does the writer make when she gives a cat a home？

A．She expects the cat to obey her.

B．The cat must observe a few necessary rules.

C．The cat must accept the writer's authority.

D．The cat will stay only if she behaves herself.

A、public void Cat() { … }

B、public Cat(string name) { … }

C、public cat(string name, int age) { … }

D、public Cat() { … }