Mingming is going home with a dog and two lambs. 明明牽著一只狗和兩只小羊回家。

On the way home， he comes to a river without a bridge. 他們在回家的路上經(jīng)過一條河，但是河上沒有橋。

There is only one small boat. And each time he can only carry one dog or one lamb to the other side of the river. 只有一條小船，并且船很小，他每次只能帶一只狗或一只小羊過河。

He can not let the dog and the lamb alone， or the dog will kill the lamb. 他不能讓狗和小羊單獨在一起，否則狗會吃掉小羊。

提問

Would you please help him? How can he carry both the dog and lamb to the other side of the river safely? 你能幫他想想辦法，把狗和小羊都帶安全帶過河嗎？

keys

先把狗帶到對岸，然后返回，把一只小羊帶過去，順便把狗帶回原岸，把另一只小樣帶到對岸。然后再返回，把狗帶到對岸去。