农夫过河：农夫带着一只狼、一只羊、一颗白菜，要从河的左岸过去河的右岸。狼要吃羊，羊要吃白菜，只有农夫在的的时候才不会右被吃的情况发生，要怎么过河呢？-farmer across the river : a farmer with a wolf, a goat, a Chinese cabbage, from the left bank of the river past the right bank of the river. Wolf to Qiyang, the sheep eat cabbage, the only farmer in the time would not be right to eat happen, how the river?