GSM900系统采用频分双工FDD方式，其双工间隔为（ ）。
A. 25MHZ
B. 45MHZ
C. 75MHZ
D. 95MHZ
下述哪一组方法,是一个类中方法重载的正确写法?
A. int addValue(int a,int b) {return a+b;}float addValue(float a,float b) {return a+b;}
B. int addValue(int a,int b) {value=a+b;}float addValue(int a,int b) {return(float)(a+b);}
C. int addValue(int a,int b) {return a+1;}int addValue(int a,int b) {return a+b;}
D. int addValue(int a,int b) {return a+1;}int addValue(int x,int y) {return x+y;}
对于下列代码:public class SupperClass{public int sum(int a,int b) {return a+b;}}class Subclass extends SupperClass{ }下述哪个方法可以加入类SubClass?( )
A. int sum(int a,int b) {return a+b;}
B. public void sum(int a,int b) {return;}
C. public float sum(int a,int b) {return a+b;}
D. public int sum(int a,int b) {return a+b;}
对于下列代码:public class SupperClass{public int sum(int a,int b) {return a+b;}}class SubClass extends SupperClass{ }下述哪个方法不可以加入类SubClass?( )
A. int sub(int a,int b){return a-b;}
B. public int sum(int a,int b,int c){return a+b+c;}
C. public float sum(int a,int b) {return a+b;}
D. public int sum(int a,int b) {return a+b;}
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