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.

开发软件时对提高开发人员工作效率至关重要的是

A．操作系统的资源管理功能

B．先进的软件开发工具和环境

C．程序人员的数量

D．计算机的并行处理能力