"ungrateful heirs"
"How sharper than a serpent's tooth it is / To have a thankless child!"
"grading papers is a thankless task"
When friends come a long way..it seems pretty thankless to send them away without so much as a cup of tea.
出自:R. PilcherThe..Queen..had lain down her life for her thankless children.
出自:B. W. Aldiss