[ liǎorúzhǐzhǎng ] know … like the palm of one's own hand; as plain as pointing to one's hand; be thoroughly familiar with …; clear like pointing at a palm; have fully grasped a subject, a situation, etc.; have sth. at one's fingertips; know … as a person knows his ten fingers; know … as well as a beggar knows his bag; know … like a book; know sth. like the back of one's hand; know … to one's fingertips; one has the knowledge of sth. so one's palm.; 他对这一带地形了如指掌。he knows the terrain of this locality like the back of his hand