物理量“电动势”描述的是（） A.电源把其它形式的能量转化为电能的能力 B.电源加在
题型：单项选择题
问题：
物理量“电动势”描述的是（）
A.电源把其它形式的能量转化为电能的能力
B.电源加在电路两端驱动电子流动的力量大小
C.单位时间内流过电路的电荷数量
D.电源所能供出的最大的电荷数量
题型：单项选择题
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1. The ad is intended for those who .
A. prefer listening to pop music B. are fond of playing video games
C. like reading novels D. want to look up new E
nglish words
2. Kindle is especially helpful to those .
A. whose eyesight is very bad B. whose English is not very good
C. who are blind and deaf D.
who are very slim
3. We can learn from the passage that .
A. you can download a whole book free of charge
B. you have to pay some fees when you download a whole book
C. the battery can only last a few hours before recharging
D. you can get a book downloaded in less than half a minute
4. If you have your Kindle damaged by chance within two years after you purchase the 2-year Kindle Extended Warranty plan , you .
A. can get your money back
B. can have your unit repaired free of charge
C. can get a new unit free by returning the damaged one
D. can have your unit repaired at a low cost