How to go across the river?
问题描述：
How to go across the river?
A man wants to go across a river.He has a dog,a hen and some rice.There is one small boat,and he can only take one thing one time.If he takes the dog first,the hen will eat the rice.If he takes the rice first,the dog will eat the hen.What should he do?
他该怎样让他的小狗,小鸡和大米安全过河呢?
答
1,take the hen and back
2,take the dog(or the rice),and bring the hen back
3,take the rice(or the dog) and back
4,take the hen