Cherts
(chert 的復數) n. 燧石\\n[化] 燧石
??? 情景例句
And very bright.
而且非常聰明。
If the hen does not prate,she will not lay.
不叨叨的母雞不下蛋。
If it is not a question of resting the body, then perhaps it is the brain that needs resting? This might be a plausible hypothesis were it not for two factors.
如果睡眠的功能不是在于使身體得到休息，那么也許是讓大腦得以休息？若不是下面兩點，這種假使似乎是有道理的。