an interface that has a covariant type parameter enables its methods to return more derived types than those specified by the type parameter.
如果接口具有协变类型形参,则允许其方法返回与接口类型形参指定的派生类型相比,派生程度更大的类型的实参。
a covariant delegate can be assigned another delegate of the same type, but with a more derived generic type parameter.
可以向协变委托分配同一类型的其他委托,但需使用派生程度较大的泛型类型参数。
the purpose of a calculation component is to take one or more values as an input and to produce one or more derived values as output.
计算组件(calculationcomponent)的功能是输入一个或多个值后能够生成一个或多个派生值作为输出。
the more derived ambulocetids exhibit more characters likely linked to increasing aquatic adaptation, and they probably were more adapted to the marine realm than to a freshwater environment.
更为进步的游走鲸类具有更多适应于水生生活的特征,而且可能更加适应于海水环境。
that's what interface inheritance means; if you fulfill the contract of the more derived type then you are required to also fulfill the contract of the less derived type.
接口继承就是这样的;如果你要满足派生程度较高的类型的契约的话,你就必须要满足派生程度较低的类型。