Теорія:

Study the exceptions with plural and singular nouns.
 
These things are always plural in English:
  
Scissors
Glasses
Trousers
Jeans
Shorts
Tights
Pyjamas
  
Do you like jeans?
  
280526_main.jpg

Do you wear glasses?
  
25671940-front-640x360.jpg
 
But you can say a pair of trousers/pyjamas/etc. Some plural do not end with -s.
  
Remember these nouns.
 
Singular Plural
ManMen
WomanWomen
ChildChildren
FootFeet
ToothTeeth
MouseMice
SheepSheep
FishFish
GooseGeese
DeerDeer
OxOxen
PersonPeople
CrisisCrises
BasisBases
AnalysisAnalyses
PhenomenonPhenomena
FormulaFormulae
 
People -  plural
Police - plural
 
Auxiliary-Unit police.png
 
1. The police are here.
2. People are very calm and friendly there.
Джерела:
en.wikipedia.org
www.weonglasses.com
www.millersville.edu
www.peterboroughpolice.com