有了这么多的选择，换一个灯泡是相当容易的。
It is quite easy, with all that choice, to change a light bulb.
假设有一个灯泡和五个可以在不同时间和不同地点打开它的开关。
Imagine there are one bulb and five switches to turn it on at different times in different places.
换一个灯泡当然很容易，但是要更换灯泡和其固定装置就比较难了。
It is easy to change a light bulb, sure, but it is harder to change the bulb and its fixture.
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