某同学做“探究加速度与力、质量的关系”实验，如图所示是他正要释放小车时的情形，对此另一同学提出了实验应改进的几点建议，其中合理的是 。
A．应把长木板的右端适当垫高，以平衡摩擦阻力
B．应调整滑轮高度使细绳与长木板表面平行
C．应将打点计时器接在直流电源上
D．应使小车离打点计时器远些
AB
打点计时器应该接交流电，C错；应使小车离打点计时器近些，D错；
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| Once upon a time there was one storyteller who wanted to search for a real-life story. He reached a village and took a cottage for rent. After 1 in the village throughout the month, the storyteller couldn't find one. 2 , he decided to stop his search. The next day, while sitting in the cottage, he suddenly heard a voice - a woman was 3 someone. The voice was coming from the big 4 behind his cottage. It sounded like the woman was abusing her 5 . The storyteller didn't like it, 6 he was happy to finally get his story. 7 the conversations each day, he added them to his story. Though he couldn't 8 the characters of his story, he started 9 the mother-in-law, as she seemed to be a bad woman. Before he finished his 10 , the storyteller wanted to see the 11 once, so he climbed the wall. There he saw the mother-in-law sitting in a 12 . It seemed that she was disabled. He saw the old lady trying to 13 a food item on the table near her wheelchair. But because of her 14 , she couldn't rea  ch it and the daughter-in-law looked like she was enjoying the old lady's 15 nearby. Suddenly the old lady fell from the wheelchair and started 16 her daughter-in-law. The storyteller went back and 17 changed the ending of the story and was surprised at how 18 it was compared to what he once thought it would be. Truly he found both a real-life story and a real-life 19 : Never judge a situation unless you know all the aspects well. Sometimes you can't imagine your 20 from the reality. | ||||
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