know sth or sb well;be well acquainted with; have an intimate knowledge of 他們彼此很～。They know each other very well./他對(duì)工作不～。He is new to the task./需要～當(dāng)?shù)厍闆r。One has to familiarize himself with the situation./～內(nèi)情know the inside story of;be in the know