Q.I covered my tomato plants with newspaper
I covered my tomato plants with newspaper. How long can I leave it? It is going to freeze tonight and they are not sure about tomorrow night, so can I leave it on all day tomorrow too?

You should remove coverings in the morning, and replace again if another freeze is expected that night. This article will tell you more about protecting plants from cold: https://www.gardeningknowhow.com/plant-problems/environmental/protect-plants-in-freeze.htm