一大笔捐款可能不及数额小但数量大的捐款，这有时要视参与度而定。
Wealthier donors can be prevailed upon to match donations of younger donors, sometimes contingent on participation levels.
过滤通常被用于分离小颗粒，从砂粒到离子都可以，由具体使用的方法而定。水力旋流器和离心机则利用离心力场将粒子抛出悬浮液。
Filtration can currently separate particles from sand to ions, depending on the process used. Hydrocyclones and centrifuges employ centrifugal fields to fling the particles right out of suspension.
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