碗扣式钢管脚手架不得采用两边向中间合拢的方法搭设，否则中间的杆件会难以安装。()
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碗扣式钢管脚手架立杆是在一定长度的钢管上每隔0.6 m安装一套碗扣接头，并在其顶端焊接立杆连接管而成。()
The edible plants available to Aborigines vary according to ______.
If ______ some plants are closely related to the species they replaced, their use was probably based on ______.
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