can you grow fruit trees or tropical plants in new england if you keep them inside when its cold?
i have been thinking of growing fruit trees and some tropical plants but i live in rhode island and …… any way i wanted to know if i could grow them outside now and bring them in during fall and winter and put them in a sunny window?

You would need a specifically controlled environment, like a greenhouse where you could change the temperature and humidity as needed. Tropical plants don’t just require heat and light, they require high humidity.
I heard from some people living in Michigan that they have grown palm trees there and bring them inside in the winter, I don’t think you can grow citrus trees there, they won’t die but I don’t think you can get fruit, (not enough sun) Your previous person said that all tropical plants need high humidity, not so, think of Palm springs or Las Vegas (very dry)