class One { public One foo() { return this; } } class Two extends One { public One foo() { return this; } } class Three extends Two { // insert method here } Which two methods, inserted individually, correctly complete the Three class?()
- A、 public void foo() { }
- B、 public int foo() { return 3; }
- C、 public Two foo() { return this; }
- D、 public One foo() { return this; }
- E、 public Object foo() { return this; }
正确答案:C,D
答案解析:有
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