不可告人的动机 /bùkěgàorén de dòngjī/ angolul

ulterior motive▼(alternative or hidden reason for doing something)
noun
[UK: ʌl.ˈtɪə.rɪə(r) ˈməʊ.tɪv] [US: ʌl.ˈtɪ.riər ˈmoʊ.tɪv]