How long are you collecting it?这句话对吗?

How long are you collecting it?这句话对吗? how long sport do you do?这句话对吗?为什么? how long have you kept this book?这句话对吗? How long have you had your watch?这句话对吗? How long have you been away there这句话对吗 How long have you been collecting shells?, how a long snake!这句话对吗 How long does it take from your to school?这句话对吗? 英语：how long have you been collecting shells?主要语法 --- How long have you been collecting coins?--- ________.A.S How long have you been collecting shells?翻译 How long have you been collecting shells?与How long have you