'ir' or 'ur' in c___cus
'ir' in circus
'ir' or 'ur' in sh___t
'ir' in shirt
'ir' or 'ur' in th___sty
'ir' in thirsty
'ir' or 'ur' in hamb___ger
'ur' in hamburger
'ir' or 'ur' in p___ple
'ur' in purple
'ir' or 'ur' in t___key
'ur' in turkey
'ir' or 'ur' in s___f
'ur' in surf
