Spanish language Q&A Forum

In the quiz I just did, the question was: “¡Qué ________ tiene ese hombre!” and the answer was manazas.  Is there a reason that Mano with an “o” ending becomes Manazas and not Manazos?  Is it simply because Mano is feminine even though it ends with an “o”?

Though it is a bit formal sounding, another way to translate the passive form in English referring to a  '"general you", i.e. people in general ',  is "ONE must/can...". For example "One must always tell the truth".

I find that helps me differentiate between "you must" - debes (a specific person), and the passive "One must" - se debe (people/individuals in general) 

The lesson says  "Remember that when you use this structure with an adjective, the adjective must agree with the subject." but none of the examples actually demonstrate this. It might be a good idea to throw in some feminine and plural adjective examples to more explicitly demonstrate the agreement!

In the writing challenge 'Melon with ham' we are asked to translate "You just need to cut some melon slices"

I wrote "Solo necesitas cortar algunas rodajas de melón" and it was corrected with "unas rodajas".

I understood these were interchangeable, and I'm yet to find any definitive to the contrary. Could someone please explain my error here?

Saludos