用sell……to和buy……from造句,至少三个一定要准确!

I m from a canada

He sells an expensive computer to me.
She buy a new caot from a shop.
可以变换时态吗？
最好用过去式
sell 变成 sold
buy 变成 bought

He sold two beautiful gifts to me.
Yesterday my mum bought two books from the library.
Do not sell these things to anyone.