Motivation can promote human activities, meet individual needs, and it is also the internal stimulus and the direct cause of human behavior.

动机不但能直接推动人类活动、满足个体需要，而且是人类行为的直接原因和内部动力。

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The major component of concentration is the ability to focus ones attention on the task at hand and thereby not to be disturbed or affected by irrelevant external and internal stimulus.

专注主要是指把注意力集中于即将到来的任务，而不受不相关的内部或外部刺激所干扰和影响。

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It could be the result of the resource adapter receiving some external stimulus from a back-end system. Or it could just be some internal event, possibly even timer driven.

它可以是资源适配器接收到后端系统的一些外部刺激之后的结果，也可以仅仅是一些内部事件，甚至可能是由计时器驱动的事件。

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But she warned that being creative "involves being able to develop internal stimulus".

BBC: Children should be allowed to get bored, expert says