Как правильно сказать at the lesson или on the lesson

At the lesson

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My favourite singer is Rihanna. She was born in Sain Michael, Barbados on 20 February. Nowdays Rihanna is already quite famous singer with musical influences from pop, R'n'b, reggae, dancehall and dance. She became wellknow all over the world. With her hits such as "SOS", Unfaithul and the lates "Cry", "Umbrella", "Don´t stop the music". When she was 15 she made her first big break. When of her friends introduced her famous musical producer Evan Rogers. He was on holidays in Barbados with his life. Rogers helped Rihanna record material in the United States of America and send to music companies. Her full name is Rihanna Robyn Fenty. I like her beutiful voice. Also I like her lifestyle. Few years ago she was a model. In my opinion the best song is Shut up and drive.

Dear Emily,
Thank you for your letter. It was great to hear about your new house.
As for my new school it's very big! It has three computer rooms and wonderful sport facilities. Actually, it seems a nice place and I enjoy studying there. The kids in my class are very friendly.
I've already made some new friends and often meet after classes.
I've got only one new subject this year. It's Economics and I'm beginning to think that it's not difficult, after all!
By the way, what music styles do you enjoy? Have you got any favorite bands? Would you like to go to their concert? As for me, I prefer Radiohead. They are cool!
I'd better go now.
нууу. .. это как бы письмо не хозяину. ...