问题 填空题

在树形结构中,树根结点没有 【1】

答案

参考答案:前件

解析: 在树形结构中,每一个结点只有一个前件,称为父结点,没有前件的结点只有一个,称为树的根结点;每一个结点可以有多个后件,它们都称为该结点的子结点。没有后件的结点称为叶子结点。

阅读理解

阅读理解。

Brenda Larson 

     Brenda is in a domino (多米诺顿骨牌) club. Brenda says, "Some people think our hobby is stupid, but

I think it's fun." The club members put dominoes in very long rows. Then they touch the first domino in the

row, and all the other dominoes fall down one after another. The club members usually meet on Saturdays

and Sundays in a gym or in a big open area. They need a lot of space for the dominoes. They need a lot of

space for the dominoes. They need to put the dominoes in just the right places. They don't fall down when

they aren't right. Brenda says that her club wants to set a world record!"Come and join us," she invited.

Keith Warner

     Keith Warner goes paragliding (滑翔伞) in his free time. He likes to see the fantastic view from the

sky. Keith says,"People say it's a dangerous sport, and they call us crazy." But Keith feels safer on his glider

(滑翔机) than in a car. He warns that there are some important safety rules. Before you jump, you need to

ask these questions: is my equipment (设备) working well? Can I land safely? He says, "Gliders are not toys.

They are aircraft (飞行器). You need to have a good instructor, and to fly, fly, and fly."

根据材料内容,判断下面句子正(T)误(F)。

( )1. Brenda thinks that the hobby of dominoes is stupid.

( )2. Dominoes won't fall down if they are in the wrong places.

(     )3. Brenda's domino club has set a world record of playing dominoes.

( )4. Keith Warner goes paragliding because he likes to see the fantastic view from the sky.

( )5. Keith thinks it's safer in a car than in his glider.

单项选择题