"These are my grandparents."
Translation:Das sind meine Großeltern.
Reverso thinks it is fine. Try it. http://www.reverso.net/translationresults.aspx?lang=EN&direction=english-german
Why can't it be "diese" at the beginning? I'm seeing a bunch of people with the same question but the answers they're getting... well aren't really answers. Why is it "das" instead of "diese"? AND I also keep seeing it would be "dies" instead of "diese" if we were to use one of those words, why is that?
There is a good explanation of when to use Das - Dies - Diese here:
Here's the relevant part but the entire page is worth reading:
While it is not exactly wrong to say "diese [Personen] sind meine Kinder", no one in Germany says that, because it's just not necessary to add or imply the noun or link the demonstrative grammatically to the children like you do in English. You just point to whatever you mean, so you would use das/ dies like in the last example of my post above. Most likely is just to say "Das sind meine Kinder".