"extend the lesson" is correct and usable in written English.
You could use it when you want to suggest that a lesson should continue for a longer period of time. For example: "Perhaps we can extend the lesson by 15 minutes to ensure that everyone understands the material."
Note: In my class, I had computers available during this class time to find more reliable information if needed, or to extend the lesson.
The teacher may choose to extend the lesson over a second class period, allowing students to deliver their op-eds orally and work in pairs to provide and receive feedback before students submit their op-eds to the school or local newspaper for possible publication.
You have errands for another two hours and you want me to extend the lesson until eight?
To extend the lesson, talk about the monster's habits.
The bigger, longer-established information-technology firms, however, will go from strength to strength.The reformists in the government want to extend the lessons of the success of the IT industry to the rest of the economy: keep government out of the way and allow Indian entrepreneurs to flourish.
Finally, we will discuss the future direction of in vitro microbial culture models and how to extend the lessons learned from microbial systems to eukaryotic cells.
The significance of these quantitative findings is enhanced when one can extend the lessons learned in certain domains where other modes of analyses are limited.
Attempts to extend the lessons learnt from Hydra to more complex organisms including humans will be challenging.
There you can find a more detailed description of the teaching process, additional student examples, technology suggestions, ideas for extending the lesson, and adaptations for making the same idea work with local campaigns.
He has extended the lesson he learned about family being the most important thing to so many others.
