题目内容：

关于英语简单句结构的问题
我的语法书是这样写的:
S+V:The sun rises in the east.
S+V+O:My brother bought a new cellphone.
S+V+P:The grass turns green.
S+V+Oi+Od:My father gave me a gife.
S+V+O+C:He made the baby laugh.
请问：P Oi 在句中有什么作用?