—Waiter, ______ ?

—Sure. Here’s your bill.

A．can I have the check, please

B．what do you want to eat

C．may I take your order

D．would you like some coffee

一个好的模式设计应符合下列原则______。

A．表达性

B．分离性

C．最小冗余性

D．以上三条