The word moose is singular or plural.
alumnus
The singular form of were is was:I was at the beach.Jane was at the beach.We were at the beach.All of us were at the beach.The exception is the singular you still uses were, it doesn't distinguish...
I AM, You (singular) ARE, He/She/It IS . . . . . Plural We/You/They ARE
The singular form is also "your" - although the archaic version would be "thy".