底部没有线条可以作为指示。
用硅作为指示性元素，研究了酸沉降作用下土壤矿物的风化特征；
The weathering characteristics of soil minerals were investigated using Si as an index element.
今天使用的许多万用表仍在利用电磁表头的运动来作为指示刻度之用。
Many multimeters used today still use the magnetoelectric meter movement as an indicating device.
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