That would be: "Dat is een tomaat"
This, that and it are not completely interchangeable, neither in English nor in Dutch.
Thanks for the answer! I think i got resonated with german and swedish here. But is "it" allways "het" - even if we are talking about "de tomaat"?
Yes. "Het" has two different meanings- one is "the" for neuter words and one is the equivalent of the English "It". When used like an "it" it is not effected from the word gender.
To any native Dutch out there: is the s in "is" pronounced like 'ss' or 'sh'? And how is it pronounced in other words?