下列各式计算正确的是（　　）

下列关于秦岭—淮河一线的叙述，错误的是(　　)

“探究加速度与力、质量的关系”的实验装置如图所示．实验中，为使小车运动时所受的拉力近似等于盘和重物的总重力，则盘和重物的总质量m与小车的质量M应满足的关系是（   ）

增加：在缺词处加一个漏字符号（/\），并在其下面写出该加的词。

删除：把多余的词用斜线（\）划掉。

修改：在错的词下划一横线，并在该词下面写出修改后的词。

注意：1）每处错误及其修改均仅限一词；

      2）只允许修改10处，多者（从第11处起）不计分。

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