Which words in this sentence are common nouns?

During Montezuma's rule, the Aztec empire stretched from ocean to ocean.



Answer :

Common nouns are type of nouns which are not particular or specific in a certain subject –person, place, thing, event or an idea. In the sentence we can identify the commons nouns which are:
 1.          Rule – if we take out the proper noun of Montezuma, whose rule is it? Then which is now a common noun
2.         
Empire – if we also examine empire without the Aztec, whose empire is it? Very broad and unspecified.

3.          Ocean – here is the most obvious of the common nouns in the sentence “ocean to ocean”. Which ocean specifically?