body clock

1. N-COUNT Your body clock is the internal biological mechanism that causes your body to automatically behave in particular ways at particular times of the day. 生物鍾[usu sing]

Jet lag is caused because the body clock does not readjust immediately to the time change. 時(shí)差是因爲(wèi)生物鍾沒有立即適應(yīng)時(shí)間的改變而引起的。