How long have they danced? (1 hour)
They have danced for an hour.
How long has he studied English? (2 months)
He has studied English for 2 months.
How long has he typed? (five hours)
He has typed for five hours.
She has walked for five days.
How long has she walked?
How long has he taught English? (2 years)
He has taught English for 2 years.
She has skated for 2 years.
How long has she skated?
How long have they worked together? (1999)
They have worked together since 1999.
How long has he driven race cars? (2011)
He has driven race cars since 2011.
He has written his name for five days.
How long has he written his name?
How long have they known each other? (4 years old)
They have known each other since they were 4 years old.