This is a story about a famous scientist. After reading it，you may know what made him 1 from others.He said all his success came from an experience that happened2 he was five years old.At that time，he tried to take 3 bottle of milk away from the fridge.However，the bottle 4 and the milk was all over the kitchen floor.

    When his mother came in，instead of shouting at 5，she said，"Ben，what a great mess you have made!I have never 6 such a big puddle of milk.Would you like to play in the milk 7 a few minutes before we clean it up？

    Actually，he did.After a few minutes，his mother said，"Ben，you have made a mess like this，8 you need to clean it up.9 would you like to do that？With a towel or a mop（拖把）？"He  10 the towel and they cleaned up the milk together.

    Then his mother said，"You were not able 11 a big milk bottle with your small hands in the kitchen.Let's 12 the bottle with water and see if you can discover a way to carry it without  13 it."Finally，the

boy learned that if he held the bottle with14 hands，he could carry it and it wouldn't drop.

    From then on，the boy knew he didn't need to be afraid15 making mistakes.It was more important for him to find a way to correct the mistakes.

下列（        ）是国家生活中最根本的问题。