How long have you kept the book borrowed from the library=How many days ______ _____ since you borrowed this book from the library?

How long have you been how long have you been learning english? How long have you been studying? How long have you been in China? how long have you been dancing today? how long have you studied in this How long have you been there? How long have you live in China How long have you ----(live)here? “How long have you been watching how long have you done与how long have you been的区别 How long have you been skating?与How long did you skate?的区别 How Long have you felt thisHow Long have you felt this way?翻译成汉语 How long have you been here?为什么是How long have you been here,不是How long have you been standing here? How long have you been collecting shells?翻译 英语：how long have you been collecting shells?主要语法 翻 译 How long have you been like this? HOW long have you been studying english 怎么回答