This paper examines some phenomena related to the pa- verbs in Amis within the framework of Role and Reference Grammar (RRG, Valin & LaPolla 1997, Van Valin 2005). The following findings and analyses are proposed in the discussion. First, pa- causative predicates can be further differentiated into ‘cause to have’, ‘cause to become (for somebody)’, and ‘cause to do’, depending respectively on the meaning of the attached roots as objects, result states, or activities. Second, the simple pa- causative verb involves a more direct and stronger causation, compared with its pa-pi- counterpart. It is argued that the jussive or weak causative sense carried in pa-pi- is due to the semantics of pi-, which is the connegative form of mi- ‘(go to) do…’ This prefix enhances the agentivity of the causee and thus decreases the controlling sense from the causer. Third, for three-place pa- predicates, the undergoer (i.e. the O argument) selection between theme/patient and effector/recipient/beneficiary participants varies among the predicates. This indicates that Amis displays a mixed type of choosing the undergoer. However, for the majority of examples discussed, there is a preference of choosing the effector/recipient/beneficiary to be the undergoer, which shows that Amis behaves more like a primary-object language (Dryer 1986), as in contrast to the direct-object language (e.g. English).