Is photo a countable noun? What's its plural form?

Is photo a countable noun? What's its plural form?


yes
photos
In general, when the consonant letter with O becomes plural, it needs to add es, this exception!



How to choose the singular and plural of collective nouns? For example, family, class, police, etc,


When family class emphasizes the whole, the predicate verb is singular. When each member of the whole is emphasized, the predicate verb is plural. Police usually appears in the plural
His family is big .
His family are very happy.
My class is a united class.
My class are happy and healthy .
The police are working in the street .



How to judge the singular and plural of collective nouns such as class, team and audience?


Emphasize that the whole is singular, emphasize the behavior of specific people, plural
My family is poor.
My family are watching Tv.
Our class is big and bright.
The class are having an English lesson.



Is people a countable noun or an uncountable noun?
Why is it modified with many / fee when it is said to be uncountable?


people['pi:pl]n.( pl.people )( pl.peoples )Nationality, race, people, people, people, common people, citizens, people in a certain area (group, industry, class), family members, relatives, ancestors, followers, servants, parish members, animals, creatures, etc