了如指掌

了的英语翻译：

end; finish; know clearly; oversee; settle; understand

如的英语翻译：

according to; as; as if; for instance; like; such as

指的英语翻译：

depend on; digit; finger; indicate; point
【医】 dactyl; dactylo-; dactylus; digit; digiti; digiti manus; digitus
finger

掌的英语翻译：

control; horseshoe; palm; shoe sole; sole
【医】 metacarpus; palm; palma; palma manus; palmae; torus manus; vola