When we use a negative construction (with not) in the main clause, until means 'not before'. I won't (will not) start cooking until you come home. until three kilometres.
Medicare Part A is hospital insurance that covers inpatient hospital care and certain home care. Medicare Part A is usually free if you or your spouse paid Medicare taxes while working. If not, it can cost up to $413 each month in 2017. Hospital and skilled nursing facility stays come with deductibles and co-insurance.
Medicare Part B helps pay for health care services such as doctor services, preventive benefits, hospital outpatient surgery and care, ambulance services, outpatient mental health services, durable medical equipment, and home health care (not covered by Part A).