他了如指掌英文

know sth like the palm of one's hand/ know like a book/ have sth at one's fingertips 以上是"了如指掌"的英语表达 例句: He had the whole design of the machine at his fingertips.他对这种机器的整个设计了如指掌参考资料：汉英成语字典

know as one know his ten fingers;

know as well as a beggar knows his bag

【英文】know something like the palm of one's hand【德文】etwassogutkennenwieseineeigeneHand【日文】掌(たなごころ)を指す