类和类之间的关系有哪几种？ A: has-a uses-a is-a B: has-a uses-a C: uses-a is-a D: has-a is-a

A has-a relationship is implemented via inheritance.

Given： Which two are true？（） A: The output is mm. B: The output is mc. C: Component is-a Meter. D: Component has-a Meter. E: DeluxeThingy is-a Component. F: DeluxeThingy has-a Component.

Inheritance is also known as the ( ) A: uses-a relationship. B: has-a relationship. C: knows-a relationship. D: is-a relationship.

类之间存在以下几种常见的关系（ ）。 A: “USES-A”关系 B: “HAS-A”关系 C: “IS-A”关系 D: “INHERIT-A”关系

类的继承反映了事物之间的________关系。 A: “有一个”(has-a) B: “是一种”（“is-a”） C: 包含 D: 有序

-Where is your father?-He ________ Australia and he ________ Sydney for two weeks. A: has been to;has been in B: has gone to;has been in C: has been in;has been to D: has gone to;has been to

10. With his hard work, John ____ the basic knowledge of computer.A. has caught B. has acquired C. has required D. has acknowledged A: A. has caught B: B. has acquired C: C. has required D: D. has acknowledged

—Where are the twins? —One ________ flowers and trees in the garden, the other ______ to help her. A: has watered, has gone B: is watering, has been C: is watering, has gone D: has watered, has been

John has never been on time, ( )? A: as John B: has not John C: has he D: has not he