Ay, there were rockets he had bought to let off on Sunday, for every one to see.
是的，他买了一些火箭在星期天发射， 让每个人都能看到。
英语百科
Buy to let
Buy-to-let is a British phrase referring to the purchase of a property specifically to let out, that is to rent it out. A buy to let mortgage is a mortgage specifically designed for this purpose.