The class provides a series of static and abstract methods to work with one of the two sets of preferences: one for user preferences and one for system preferences.

这个类提供了一系列静态和抽象方法来操作两套首选项(其中一套是用户首选项，另一套是系统首选项)中的其中一套。

youdao

The next step is to change the default sound system preferences.

下一步，更改系统声音配置。

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If you open up system preferences now, you can see that your desktop is set to cycle through these images.

如果你此时打开“系统偏好设置”，你就会看到你的桌面已经被设置为这些图片的循环了。

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However,to become more competitive in the global economy, the government is trying to rollback its system of ethnic preferences, which requires companies to reserve 30 percent of their shares for Malays.

VOA: standard.2010.02.24

That feature, and other settings for people with low vision, can be found in the Universal Access section of System Preferences.

WSJ: Mossberg's Mailbox: Larger Mac Font

The EU would remove tariffs and quotas, reinstating the Generalised System of Preferences (GSP).

BBC: EU plans to lift trade barriers for Burma exports

Consistent with section 201(a)(2) of the Implementation Act, Panama is to be removed from the enumeration of designated beneficiary developing countries eligible for the benefits of the Generalized System of Preferences (GSP).

WHITEHOUSE: The White House