How long have you...?

She's been on holiday since Friday

Not long. Just 5 minutes

How long have they been watching TV?

I've been learning english since 2014

How long has he lived in Spain?

How long has Mary been married?

How long has she been on holiday?

She has been married for 5 years.

How long have you known Susan?

How long have you been waiting?

They've been watching Tv for 2 hours.

About ten years.

I've known her for 5 years

How long have you been learning English?