Try to nap in the morning or just after lunch; human circadian rhythms make late afternoons a more likely time to fall into deep (slow-wave) sleep, which will leave you groggy.

• 试著在早上或午餐过后进行短眠；人类一天的生理时钟，会使得在愈接近黄昏的时候，睡意会愈来愈重，这会使你很无力。