从某种意义上讲，设备振动诊断的过程，就是从信号中提取（）的过程。组成周期成分的（）振

阅读理解，根据短文内容判断正(T)误(F)。

      Today is Sunday. My family are all at home. We would like to do some housework. My father can sweep

the floor and clean the windows. My mother can wash the clothes and cook the meals. I can water the flowers

and empty the trash. We are helpful.

( ) 1. There are three people in my family.

( ) 2. It's Saturday today.

( ) 3. My father can't clean the windows.

( ) 4. My mother can cook the meals.

( ) 5. I can empty the trash.

( ) 6. We are helpful at home.

在国产灭磁开关中，（）属于采用长弧原理灭磁栅的移能型灭磁开关。

A.DM2

B.DM4

C.DMX

债权人转让权利的，应当通知债务人。未经通知( )

A．该转让无效
B．该转让的效力待定
C．该转让对债务人不发生效力
D．债权人应承担违约责任

按( )分类，可将税收分为价内税和价外税。价内税与价外税的划分主要是针对于商品课税而言的。凡税金包含在商品的价格之中，构成价格组成部分的，称为价内税。凡税金不包含在商品价格中，而作为价格之外附加的则称为价外税。

A．按课税标准

B．按税种的隶属关系

C．按税收与价格的关系

D．按征税对象

碗扣式钢管脚手架的斜杆应尽量布置在框架（）上。