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小学四年级-三角形3-三角形的特性3 三角形具有稳定性
小学四年级-三角形3-三角形的特性3 三角形具有稳定性，通过摆小棒说明三角形具有稳定性，四边形没有稳定性，四变形可以变形
小学四年级54/94
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