英语翻译请翻译以下短语（要写完全部意思）：drop in drop in doing sth drop in at a

英语翻译请翻译以下短语（要写完全部意思）：drop in drop in doing sth drop in at a drop in on sb./ drop in at a place翻译 drop in on与drop in at drop in什么意思? 英语翻译drop offdrop in drop downdropping off drop by,drop on和drop in drop-in 和drop out drop in or drop by? drop in at 和drop in to 有什么区别 drop litter in a public place翻译 drop in grades什么意思? drop in at和drop in to到底什么区别drop in