The problem about mechanical efficiency of tackle-block is the key point in junior high school mechanics and also the difficult point.
滑轮组机械效率问题是初中力学中的重点，也是初中力学解题的难点。
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A simple tactic: pick one half-hour block each day in which to tackle all of the small, non-academic tasks that need to get done. Right before or after dinner is a good time.