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问题 选择题
3A的直流电通过电阻R时，t时间内产生的热量为Q；现让一交流电通过电阻R，若2t时间内产生的热量为Q，则该交流电流的有效值和最大值分别为（　　）

A．I有=3/2A，Im=3A

B．I有=3A，I有=3A

C．I有= A，I有 A

D．I有3A，Im=6A

答案

答案：A

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     Here  1  good news for children and their parents. Smoking is going to be banned (禁止) in primary and
middle schools in China. We all know smoking  2  our health. So schools will ask their teachers to stop  3  
on campus (校园). According to a report, there're  4  young smokers in China. Young people are the hope of
our country. Let's say no to smoking for our country and for  5 .
( )1. A. are       
( )2. A. is bad for
( )3. A. smoke     
( )4. A. million of
( )5. A. we         		B. is            
B. is good for   
B. to smoke      
B. two millions of
B. our            		C. am         
C. is bad at  
C. smoking    
C. two millions
C. ourself     		D. be         
D. is good to 
D. smoked     
D. millions of
D. ourselves                 
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选择题

一次函数y=-x-3与x轴交点的坐标是（　　）

A．（0，-3）

B．（-3，0）

C．（0，3）

D．（3，0）
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