一个猎人带着一只羊，一只狼和一棵白菜回家，路上遇到一条河。河边只有一条船，但船太小，一次最多只可载猎人和另一样东西过河。但猎人不在时，狼要吃羊，羊要吃白菜。请问怎样才能把狼，羊，白菜都安全运过河？
A hunter returns home with a sheep, a wolf and a cabbage and meets a river. There is only one boat by the river, but the boat is too small to carry hunters at one time and cross the river with another. But when hunters are not there, wolves need to eat sheep and goats eat cabbage. How can the wolf, sheep, cabbage are safely transported across the river?