Cuando quieres preguntar si algo es algo, es mejor decir
"Is.......correct?
"Is this correct?" Envés de "this is correct?"
"Is 'I will visit my grandma on Saturday' correct?"
La pregunta es "Is+subjetivo+lo que quieres saber "
La respuesta será "subjetivo+IS+
Q:"IS she your sister?"
A:"yes, she IS my sister" or "yes, she IS."
Q:"Is this correct?"
A:"yes, this IS correct" or "yes, he IS"
Q:"IS he speaking spanish?
A:"yes, he IS speaking spanish" or "yes, he IS"