Now map that back to the Arabic numeral system and you end up with, no surprise, 9.

现在把它映射回阿拉伯数字系统，毫无疑问，你会得到9。

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This is a back-up system for world agriculture.

这是全球农业的储备系统。

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Make sure you back up your system.

确保对系统进行了备份。

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And yet it is a miracle that Voyager 2 managed to send anything back at all, for its main radio system failed soon after launch, and its back-up system proved to be faulty.

ECONOMIST: The long arm of the celestial repairman

The Post reported that a malfunction in Mir's attitude-control system also occurred in March, causing it to list until an alternate back-up system was activated.

CENTERFORSECURITYPOLICY: Center For Security Policy

This means that if energy is required on a constant basis then the system needs to be backed-up by conventional sources of power 73% of the time, and there are days when the back-up system is required for more than 90% of the time (In Germany, the industry association insists that renewables uptime averages 10%).

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