Police have ruled out robbery as a motive for the killing.

警方已排除了出于抢劫的动机而杀人的可能。

the motives and objectives of British foreign policy.

英国对外政策的动机和目标。

The doctor's motive was to bring an end to his patient's suffering.

这位医生的初衷是不再让他的病人承受痛苦。