已知集合A={x|y=x2，x∈Z}，B={y|y=x2，x∈Z}，则A与B的关

搜题请搜索小程序“爱下问搜题”

问题选择题

已知集合A={x|y=x²，x∈Z}，B={y|y=x²，x∈Z}，则A与B的关系是（　　）

A．A⊊B

B．B∈A

C．B⊊A

D．A∩B=∅

答案

答案：C

填空题

用所给词的适当形式填空。

1. My idea is_____ (difference)from yours.

2. You should look after yourself well and keep _____ (health).

3. Everyone should have a good habit of brushing _____ ( tooth).

4. —Sally, your dress looks so nice!

—Thank you. It _____ (make) of silk.

单项选择题

放射工作人员防止眼晶状体发生非随机性效应的年剂量当量限值是

A．5mSv
B．50mSv
C．100mSv
D．150mSv
E．500mSv