practical illustration of some principle, often given or used as a warning 实际教训
*Let this accident be an object lesson in the dangers of drinking and driving. 这一事故可以作为醉酒驾驶危害的实际教训.
1. Every solid object will reflect a sound, varying according to the size and nature of the object. 任何固体者反射声音，反射的声音因物体的大小和性质的不同而不同。
2. Fulfilling its designer´s dream to create ´an enormous object drawn as faintly as possible´. 实现了设计者企图创造一个"尽量用细线条勾画出一个庞然大物"的梦想。
3. Why? I´ve got to teach him a lesson because he always tries to seduce my fiancee. 为什么?我必须给他一个教训,因为他老是试图勾引我的未婚妻.
4. When the lesson in grammar was over we began our writing. 文法讲完了就开始习字。
5. There´s the bell for the end of the lesson. 下课铃响了.
6. The teacher illustrated the history lesson with pictures of castles. 教师利用城堡图画讲解历史课。
7. The first lesson in driving is how to start the car. 学驾驶汽车的第一课是启动.
8. The lesson was not clear and it has muddled me. 这一堂课不清楚，把我给搞糊涂了。
9. The children rushed out of the classroom at the end of their lesson. 下课后孩子们冲出教室。
10. The master had told us he would question us on verbs, and I did not know a thing about them, for I had not studied my lesson. 老师说过要问我们动词的问题，可是我没有温习功课，一点也不会。