How long have you been learning E?
How long has your teacher been working here? / How long has your teacher worked here?
How long have you known your best friend?
How long have you been at this school?
How long has your best friend living in this town? / How long has your best frriend lived here?
How long have you had your nmobile phone?
Со словами live и work можно использовать и Present Perfect Simple, и Present Perfect Continuous