皮皮学，免费搜题
登录
搜题
【多选题】
下列对电动机变频调速系统的描述中哪几项是错误的？（）A.
交一交变频系统，直接将电网工频电源变换为频率、电压均可控制的交流，由于不经过中间直流环节，也称直接变频器
B.
交一直一交变频系统，按直流电源的性质，可分为电流型和电压型
C.
电压型交一直一交变频的元件为电感
D.
电流型交一直一交变频的元件为电容
拍照语音搜题，微信中搜索"皮皮学"使用
参考答案：
参考解析：
知识点：
皮皮学刷刷变学霸
举一反三
【单选题】The man was a soldier all his life.
A.
The man died.
B.
The man is alive.
C.
The man is a soldier now.
D.
No right answer.
【简答题】听对话，选择相应的图片。 1. What does the man want? 2. How will the man go to work? 3. What will Lucy do? 4. Which sign are they talking about? 5. Whom are they talking about?
【单选题】What jumped out in front of the man's car?
A.
A giant deer.
B.
A strange man.
C.
A hairy alien.
【单选题】In the passage the word 'prospect' refers to______.
A.
your future boss
B.
an employer
C.
an explorer
D.
a possible customer
【简答题】听对话，选择图片。 1. Which is the man's favourite animal? 2. What does the man want? 3. Which picture is right? 4. What's the weather like now? 5. Where is Mike now?
【简答题】Y=exp(β0+β1X1+β2X2+μ)；
【单选题】What level could the man reach after the course?
A.
The man could paint like a master.
B.
The man could paint by himself.
C.
The man could paint under the guidance of the teacher.
【单选题】If X refers to export,M refers to import, then IIT share is:
A.
X＋M
B.
X－M
C.
(X＋M)/(X－M)
D.
1－|X－M|/ (X＋M)
相关题目：
【单选题】What jumped out in front of the man's car?
A.
A giant deer.
B.
A strange man.
C.
A hairy alien.