A.get B.let C.set D.is
A.public class B inherit A B.public class B :: A C.public class B : A D.public class B from A
A.允許有多個相同名稱的構造函數(shù) B.允許有多個不相同名稱的構造函數(shù) C.至少要有一個構造函數(shù) D.只能有一個構造函數(shù)