1步：先用5升倒6升二次,5升瓶剩4升；2步：再把6升瓶倒掉,把5升瓶剩的4升装到6升瓶,6升瓶刚好还差2升；3步：再拿5升瓶装满倒2升到6升瓶,5升瓶刚好3升