Computer is a useful machine.

电脑是有用的机器。

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I wish to invent a useful machine some day.

我希望有一天能发明一样有用的机器。

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In general, a state machine is useful when your component's activities are event driven and each activity that occurs depends on the current state of the component.

一般来说，如果组件的活动是事件驱动的，并且所发生的每个活动都取决于该组件的当前状态，那么状态是非常有用的。

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"To get a useful computer it needs to be probably a million times more complex, so a full-scale useful factoring machine is still at least two decades away, " he said.

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Asimo, by contrast, is an ornate, expensive and complicated piece of machinery that really only seems useful if you need a machine that can climb a stair for you.

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Apart from what has occurred in the industry itself, the complete transformation of the global machine tool industry is a useful barometer for the entire manufacturing sector.

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