If you are looking for the translation of "this is wonderful", I would simply say "è meraviglioso!" (the subject "questo" / "ciò" can remain unexpressed). "Questa è meravigliosa!" means "This thing / person (belonging to the feminine gender) is wonderful" so you can use it to refer to a feminine noun you have previously mentioned. I hope this helps. Feel free to contact me for further grammar explanations.

"Cosa è meraviglioso?" Meraviglioso è una parola italiana che significa "WONDERFUL".

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