On these pistons the number piston rings was reduced to three, two compression and one oil-control.

在这些活塞中，活塞环的数量减少到三个，即两个气环，一个油环。

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The piston rings carried in the ring groove are of two basic types: compression rings and oil-control ring.

安装在环槽中的活塞环有两种类型：压缩环和机油环。

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Oil-Control Products There are three types: oil-absorbing surface Oil-Control, deep oil control should be based on individual circumstances to choose.

控油产品有三种类型：吸油、表面控油、深层控油，应根据个人的情况来选择。

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The stockholders of seventy-seven oil companies gave control of their stock to nine trustees of Rockefeller's Standard Oil Company.

VOA: special.2010.06.03

In nineteen thirty-eight, Adair got his first oil-related job with the Otis Pressure Control Company.

VOA: special.2009.03.22

A key stumbling block was Kirkuk. Ethnic Kurds would like to see the oil-rich city under the control of the Kurdistan Regional Government.

VOA: standard.2009.11.09

Some, especially in oil-producing areas, control bigger budgets than those of national governments in some neighbouring West African countries.

BBC: Nigeria's Supreme Court dismisses five governors

State oil companies control three-quarters of the world's crude oil reserves.

ECONOMIST: The state and the economy

The purchase of TNK-BP gives the Russian government control of roughly one-third of oil production in Russia.

FORBES: From Russia With Love: BP Draws Closer To Kremlin With $30B Sale of TNK-BP Stake