求翻譯：if you could do something standing on your head, you can do it very easily, usually because you have done it many times beforeif someone could do something in their sleep, they can do it very easily, usually because they have done it so oftenMost of our guests were very quiet, but Harry could talk under water, so he ke是什么意思？

待解決 懸賞分：1 - 離問題結(jié)束還有