Sleep is such a fickle thing.When not wanted, it comes, and when it is invited, coaxed, and enticed along by every available trick, it puts on airs and conceals itself.

• 睡眠这东西脾气怪得很，不要它，它偏会来，请它，哄它，千方百计勾引它，它拿身分躲得影子都不见。