搜题请搜索小程序“爱下问搜题”
问题 选择题

使方程x5－3x－1=0至少有一个实根的区间不可能是（ ）

A．（－2，－1）

B．(－1，1)

C．（1，2）

D．（2，3）

答案

答案：D

：∵f (x)=x5－3x－1在四个区间都连续，但A，B，C三个区间端点对应的函数值异号，∴只选D

阅读理解

阅读理解。

      My name is Helen. I'm seven. Dale is my brother. He's eleven. We are in the same

(相同的) school. My mother is a teacher. She teaches English. She is a teacher in our

school. My father is a doctor in a big hospital. I have a dog. Its name is Ben. We are

good friends.

1. Dale and Helen are ______.

A. brother and sister

B. friends

C. students

D. both A and C

2. Dale's mother is ______.

A. an English teacher

B. a doctor

C. a student

D. eleven

3. Ben is the name of ______.

A. Dale's sister

B. Helen's dog

C. Helen's mother

D. Dale's father

4. Helen is ______.

A. an English teacher

B. a doctor

C. a student

D. eleven

5. Dale, Helen and their mother are ______.

A. students

B. at home

C. friends

D in the same school

查看答案
多项选择题

继发性妄想常与下列情况相关（）

A.情感障碍

B.知觉障碍

C.智能障碍

D.意识障碍

E.性格障碍
查看答案