How long _____ you _____ your laptop?
have, had
How long _____ you ______ your friend?
have, known
How long ____ you ______ in Russia?
How long have you studied English?
For/Since...
How long have you been awake today?
How long have you gone to your school?
For/Since...
How long have you known your mom?
For/Since...
How long has your friend known you?
For/Since...