如果你只會說 I know something very well, 就太low了。如果表達能更精確，更豐富，有亮點，則更好。
瞭如指掌，know something like the back of one"s hand
I know English like the back of my hand. 我對英語瞭如指掌。Tell me where you want to go. I know the city like the back of my hand. 告訴我你想去哪裡，我對這座城市瞭如指掌。
如果你想表達的是
對某事某人從裡到外很清楚，用inside out；
對某事從頭至尾很清楚，用back to front.
I know English inside out because I have learned it for more than 10 years. 我對英語裡裡外外都瞭解，因為我已經學了十多年了。I am a veteran worker who know the work from back to front. 我是個老員工，對工作從頭至尾都瞭解得透徹。As her friend since kindergarten, I know her inside out. 作為從幼兒園就開始的朋友，我對她裡裡外外都瞭解。
如果你只會說 I know something very well, 就太low了。如果表達能更精確，更豐富，有亮點，則更好。
瞭如指掌，know something like the back of one"s hand
I know English like the back of my hand. 我對英語瞭如指掌。Tell me where you want to go. I know the city like the back of my hand. 告訴我你想去哪裡，我對這座城市瞭如指掌。如果你想表達的是
對某事某人從裡到外很清楚，用inside out；
對某事從頭至尾很清楚，用back to front.
I know English inside out because I have learned it for more than 10 years. 我對英語裡裡外外都瞭解，因為我已經學了十多年了。I am a veteran worker who know the work from back to front. 我是個老員工，對工作從頭至尾都瞭解得透徹。As her friend since kindergarten, I know her inside out. 作為從幼兒園就開始的朋友，我對她裡裡外外都瞭解。