在搅拌进行中，测定搅拌不同时间四个固定位置的电导率，用测得的数据计算分离强度和平均电导。
The progress of mixing was followed by making sets of 4 positioned local measurements of electrical conductivity after stirring for different time (or different numbers of revolutions).
在更换电源之前，我们必须从望远镜上取下一个用四个螺丝固定的扶手。
Before we could replace the power supply, we would have to remove from the telescope a handrail fixed with four screws.
如果同时有固定电话来电和手机来电，那么总共有四个电话可以同时连接到VTech系统上。
If each line — landline and cellular — has call waiting, a total of four callers could potentially be linked to the VTech system at once.
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