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问题 单项选择题

GK型三通阀701型试验台试验中，制动灵敏度试验时，三通阀在减压25kPa前须发生制动作用保压后，制动管压力下降值不得大于（）。

A.20kPa

B.25kPa

C.30kPa

D.40kPa

答案

参考答案：D

补全对话，情景问答
Read and match.（读一读，连线）
( )1. Where is the art room？    
( )2. What time is it?            
( )3. What colour are your jeans?
( )4. Is this your jacket?        
( )5. What are they?              		A. They are brown.            
B. No, it isn't.              
C. It's on the second floor.                                                         
D. They are your pants.      
E. It's eleven o'clock.      
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单项选择题

乳牙常见的萌出顺序是（）

A.A-B-C-D-E

B.A-B-D-C-E

C.A-D-C-E-D

D.A-B-D-E-C

E.A-C-D-D-E
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