下列叙述正确的是（　　）

胡适曾说过：“如果我们将中国传统文化比喻成一棵大树，洋务运动只不过剪断了一些枝叶，辛亥革命则相当于将这棵大树砍断了。但是树断了，树墩还在，一般的树只要树墩还在， 还是可以萌发”。这里所谓的“树墩”是指（   ）

    Hello! Look here! There's 1 apple tree behind Dick's house. Dick is near the tree. There are some apples 2 the tree. Dick is looking 3the apples. They are big and red. Dick is hungry. He wants to 4 an apple. Dick isn't tall. He is short. He can't reach(够到) the apples. He puts a 5 under the tree. Can he reach the apples on the box now?6, he can't. He is too7. Here comes Paul. He is Dick's brother. “Hello, Dick,8 do you want to do?”

     “Please help9, Paul. I can't 10 the apples.”

     “Here you are, Dick. One is for you, and one is for me!”

     “Thank you, Paul.”

关于摩擦力的说法正确的是（   ）