I purchase for two grown male men, shunt filtering, once a year, for the duration of nineteen years'.

 I purchase, one shunt filtering for one female child under the  age of five, every year, once a year, for the duration of nineteen years'.

 I buy one community club house, for local residence, a supply of 100 normal tea bags', once a week, for the duration of one year.

 I purchase one black person, a supply of two seasonal, one kilo boxes of socks, for the duration of seven years', once a year.

All can I's, meaning I will purchase.