就是有某些基因，如果强制开启或者关闭，会对动物和发育中的胚胎造成伤害。
There are just some genes that are on, and some that are off, that are not good for the animal, for the developing embryo.
这种抽油泵柱塞游动阀采用机械强制开启和关闭的结构，柱塞为等径光管、浮动结构，可防止发生气锁游动阀、阀球关闭滞后、砂卡柱塞现象。
The travelling valve of the pump is designed to be closed and opened forcibly, and the pump plunger adopts equal-diameter bare pipe with a floating structure to prevent gas lock and sand sticking.
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