搜题请搜索小程序“爱下问搜题”
问题 选择题

若正整数a，b，c是一组勾股数，则下列各组数一定还是勾股数的是（　　）

A．a+1，b+1，c+1

B．a2，b2，c2

C．2a，2b，2c

D．a-1，b-1，c-1

答案

根据勾股数的概念知，若有a2+b2=c2，则（2a）2+（2b）2=（2c）2也成立，其它三个不成立，故选C．

改错题

此题要求改正所给短文中的错误。文中共有10处语言错误，每句中最多两个错误；每处错误仅涉及一个单词的增加，删除或修改。

删除：把多余的词用斜线（\）划掉。

增加：在缺词处加一个漏字符号（∧），并在其下写出该加的词。

修改：在错的词下划一横线，并在该词下面写出改正后的词。

注意：1. 每处错误及其修改均仅限一词；

2. 只允许修改10处，多者（从11处起）不计分。

Ken was having a serious back pain. He was in the hospital. The doctor talked to Eva, Ken’s wife, about her condition. When she asked what serious her husband’s back trouble was, the doctor said that Ken should have a completely bed rest. This meant that he has to lie down all the time for 2 or 3 weeks after he could go home. He then had to stay bed for about 10 days. After that, he could only got up twice a day to move around for 10 minute. Finally he could do some easy exercise. When he could walk round for an hour, he was able leave the hospital.
查看答案
单项选择题

被称为“斟酌使用的财政政策”是( )。

A．自动稳定的财政政策

B．周期性财政政策

C．相机抉择的财政政策

D．微观财政政策
查看答案