Identify the classification of the following items as

accrued asset

unearned revenue

accrued liability

prepaid expense

$1.$ Three months' interest on notes payable paid in advance

$2.$ Subscription fees for six months received in advance

$3.$ Services rendered but not yet billed at month$-$end

$4.$ Interest payable accrued on an accounts payable but not yet paid

$5.$ Salaries payable owed but not yet paid

$6.$ Two year's premium on building paid in advance