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问题 单项选择题

某制冷机在热源T1=300K及冷源T2=250K之间工作，其制冷量为1000kJ，消耗功为250kJ，此制冷机是( )。

A．不可逆的
B．可逆的
C．不可能的
D．可逆或不可逆的

答案

参考答案：A

阅读理解

This is Betty’s bedroom. Please come in and have a look at the pictures in the room. Let’s look at the one on the desk first(首先), please. It’s small but very good. It’s a photo of a man, Bob Brown, and a boy, Richard Brown. Mr. Brown is Richard’s father. And Richard is the son of the man. He’s twelve years old and is a middle school student. 

Can you see that big one on the wall? It is a picture of a nice woman, Helen Brown, and a lovely(可爱的)girl, Betty Brown. Helen is Bob’s wife, and she is Betty and Richard’s mother. Betty is young. She’s only six.  

小题1:It’s Richard’s bedroom. 

小题2:Bob is father of Richard. 

小题3:Betty isn’t Richard’s sister. 

小题4:Helen Brown has two children. 

小题5:Helen has a sister. 
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填空题

平刨床有手工进给和机械进给两种刨床，压刨床全都是（）进给的刨床。
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