如何测量轴颈的椭圆度？
参考答案：
用外径千分尺，在同一横断面内，测得的最大直径与最小直径差。为该断面处轴颈的椭圆度。
阅读短文，回答问题。
It's 2 o'clock on Sunday afternoon. Sally and her friends are at her home. Lily is reading a story book, she
is quiet. Peter is looking at Sally's pictures. Mary and Ben are watching TV. Where is Sally? She is in the kitchen(厨房). She is cutting the watermelon (西瓜) for them.
1. What time is it?
_______________________________________
2. What's Lily doing? Is she loud?
3. What's Peter doing?
4. What are Mary and Ben doing?
5. What's Sally doing?
农村改革30年来，我们迈出了哪三大步？
