问题 单项选择题

下列说法中,( )是正确的。

A.子类拥有的成员数目大于等于父类拥有的成员数目

B.父类代表的对象范围比子类广

C.子类要调用父类的方法,必须使用super关键字

D.一个Java类可以有多个父类

答案

参考答案:B

解析: 本题考查对子类父类关系的理解。对一个类的继承也就是构建了一个子类,子类继承了父类的方法和状态,同时还可以向新类中增添新的方法和状态。重点掌握两点:子类方法的访问权限比父类访问权限高,因此父类不能替代子类,但子类能够代替父类,子类方法不能产生比父类更多的异常。子类拥有的成员数目小于等于父类拥有的成员数目,选项A说法错误:父类代表的刘象范围比子类广,选项B说法正确;子类要调用父类的方法,可以使用super关键字,也可以将父类的方法进行重写,选项C说法错误。在Java中一个类只能有—个父类,选项D说法错误。

阅读理解

阅读理解。

     Venice is the "Queen" of the Adriatic Sea (亚得里亚海). Every year thousands of people from all over

the world travel to Italy to visit the city. Do you know why they like to go there for a visit?

     Venice is a very beautiful city. It is quite different from other cities in the world. There aren't any roads

and streets in the city. So there aren't any cars and buses. There are many canals (运河) in the city. There

is one big canal and one hundred and seventy-seven small canals. People move up and down the canals in

boats to go to work, go shopping or visit their friends.

     But Venice is sinking. It is going down and the water is going up. In 2040 Venice will be under water,

The Adriatic Sea will cover the city. The Venetians (威尼斯人) love their city and want to stay there. So

they want to save Venice from the sea. They do not want to leave. How can they save Venice? They can

build some strong huge walls and gates in the sea. The gates will close to keep too much water out. Thus

Venice will not sink.

1. From this short article we know Venice is  ________.

A. a very beautiful woman of the Adriatic Sea.

B. the most important woman in Italy.

C. a very important and beautiful place of the Adriatic Sea.

D. the most important city in Italy.

2. People from all parts of the world go to visit Venice because ________.

A. there are 177 canals in the city.

B. it is sinking into the Adriatic Sea.

C. there are a lot of kinds of boats on the canals.

D. it is not only beautiful but also quite different from other cities.

3. The Venetians usually go to work or visit their friends ________.

A. by bus.

B. by bike.

C. in cars.

D. in boats.

4. Year by year the Adriatic Sea ________ and Venice ________.

A. is rising…is sinking.

B. is going down…is going up

C. has risen… has sunk

D. will go up…will go do

5. Because the Adriatic Sea will cover it, the Venetians ________.

A. have to leave Venice in 2040.

B. will try to do something to save their city.

C. want to stay there until the water covers the city.

D. do not love the city any longer.

填空题