A.睡眠時(shí)間和睡眠時(shí)相的增加 B.睡眠時(shí)間和睡眠時(shí)相的減少 C.睡眠時(shí)間和睡眠時(shí)相的前移 D.睡眠時(shí)間和睡眠時(shí)相的紊亂
A.持續(xù)性垂直壓力 B.摩擦力 C.剪切力 D.機(jī)械力
A.3min B.4min C.5min D.6min