【单选题】父类Person有子类Chinese和American,且两个子类都重写了父类中的walk()方法;下列哪项实现了多态编程 A. Chinese c=new Chinese("张三"); American a=new American("John"); B. Chinese c=new Chinese( "张三"); American a=new American("John"); c.walk(); a.walk(); C. Person person1=new Chinese("张三" ); Person person2=new American("John"); D. Person person1=new Chinese("张三" ); Person person2=new American("John"); person1.walk(); person2.walk();

When exchanging cards, you smile and walk to the other person and extend your name cards with both hands.

According to the passage, which of the following is uncommon in the US A: A policeman questions a person who is just taking a walk. B: A dog pursues a person who walks past a house. C: A road that does not have any sidewalk. D: A person takes a walk just for pleasure.

How you choose to relax will vary from person to person, whether that’s taking a walk outside, curling up with a favorite book, or taking time to practice yoga or another soothing habit each day. A: healthy B: relaxing C: special D: stressful

1. The person in dialogue 1 wants to go to the _______________.2. The person in dialogue 2 wants to go to the ______.3. The person in dialogue 3 wants to go to the ______________________.

【单选题】_____________ On the grass, or it will “cry”. A. To walk B. Not to walk C. Walk D. Don’t walk

We got up early this morning and 1 a long walk after breakfast.

The underlined phrase "dry run" in the third paragraph means______. A: to run to work B: to test the route in advance in person C: not to make your feet wet on the way work D: to walk as quickly as possible

1. The person in dialogue 1 wants to go to the _______________.

父类Person有子类Chinese和American，且两个子类都重写了父类中的walk方法；下列哪项实现了多态编程