如图39-1所示，此台三相变压器的联结组应属下列哪项（）。 A．D，y11 B．D，

阅读理解

       One day, Mr Smith is going to take a train to his hometown. When the train starts, one of his shoes

falls to the ground. The train is going faster and faster, and he can't pick it up. Then he quickly takes off

the other shoe and throw it on the ground near the fallen(掉下的) shoe. A little boy on the train asks him, "Why do you do that? You have lost(丢失) one shoe. "Mr Smith answers, " If a man picks them up, he

may get a pair of shoes. "

1. Mr Smith is going to his hometown________.        

A. by bus          

B. by train        

C. by bike          

D. on foot

2. What happens(发生) to Mr Smith when the train starts? He lost________.        

A. his bag          

B. his watch        

C. one of his shoes  

D. nothing

3. Mr Smith can't pick up the fallen shoe because ________.

A. he doesn't want to take it back

B. the little boy picks it up

C. he thinks it is too old

D. the train starts and is going faster and faster

4. What does Mr Smith do after his shoe falls to the ground?

A. He gives the other one to the little boy.

B. He throws the other one to the ground near the fallen one.

C. He gets off the train.

D. He looks at the shoe and laughs.

5. Why does Mr Smith do that?

A. Because he doesn't like his shoes.

B. Because he wants the man who picks up his shoes to get a pair of shoes.

C. Because he wants the little boy to pick up the shoes.

D. Because somebody asks him to do that.

可乐定属α-受体激动剂。()

如果一次点火不成功，必须立即关闭（），抽空30分钟后，拔下氢气胶管，继续抽空置换，分析炉内含氢小于（）后，再重新点火。如果间隔时间超过（）个小时，应重新分析（），氢气纯度，特别是炉内含氢等各项点火指标，合格后再重新点火。

以太网帧结构中，目的地址可以是( )。
Ⅰ. 单一结点地址 Ⅱ. 多点地址 Ⅲ. 广播地址

A．Ⅰ和Ⅱ

B．Ⅰ和Ⅲ

C．Ⅱ和Ⅲ

D．全部

水平输送机正常工作时的振幅为单振幅（）。

A.10mm

B.7.5mm

C.5mm

D.2.5mm