读一读，填一填。
Old Peter likes travelling. He travelled to a lot of places in the world. One summer he took his son, little
Peter to London. They travelled by train. It was the first time that little Peter took a train. He was so excite
-d that he sometimes put his head out of the window. He wanted to see the beautiful things along the railwa
-y. Old Peter said," What are you doing, my son? Don't put your head out of the window. It's dangerous
to do that." Then little Peter felt a little unhappy.
1. _____ likes travelling.
2. Little Peter travelled by train for _____.
3. Little Peter sometimes _____ to see outside.
4. It's _____ to put his head out of the window.