"The tree is not small but big."
Translation:Ten strom není malý, ale velký.
In Czech you don't need to say 'Ten'. there is no way of telling whether you are talking about about 'that' tree or "the" tree. 'Strom neni maly, ale velky' literally translates to 'The tree is not small but big' because there is no article in Czech. "That" tree is not big but small you would have to then specify by adding the 'Ten'.
I was going to ask if 'ten' is absolutely necessary here. I'm going to report it then.