Verbs  that show actions or 'action verbs' are the most used verbs. 
 Action  verbs take 's' in the third person when they are singular verbs:
 He  lives in Athens.
 She  works in the city.
 It  rains a lot in February.
Negative  sentences need 'do not', 'does not', or 'did not'.
   He  does not live in Athens.
   She  does not work in the city.
   It  does not rain in August.
 It  did not rain in June.
Adjectives give more meaning to nouns.
Adjectives  are normally placed in front of the noun.
   An  exciting film.
   An  interesting book.
   Fast  cars.
   Red  roses.
Look at this example:
Sarah is a university student. Sarah was born in London but now Sarah lives in Paris where Sarah is studying French. Sarah’s boyfriend is Louis. Louis is French and Louis met Sarah in Paris. Sarah and Louis want to get married. Sarah’s and Louis’ parents are very happy.
Now here is the same example using pronouns:
Possessive  nouns show who owns something or who something belongs to.
   Possessive  nouns are formed with ('s)
Sarah's  car.
   Peter's  lap top.
   The  school’s headmaster.
When  the noun is plural and ends with 's', just add (')
   The  babies' toys.
 My  parents' house.
Count  nouns are nouns that can have one or more than one.
   A  pen – three pens, a bottle – six bottles, a television – three televisions, a  car – five cars.
Count  nouns can be used with;
   A  few, few, many, some, every, each, these etc.
   A  few pens, many bottles, a few cars, each television etc.
Count  nouns can be used with a/an or the
   There  is a pen on my desk.
   I  bought a bottle of Italian wine.
   Each  television in the flat was a new model.
   My  family has five cars.
Being able to identify between countable and uncountable nouns is necessary to use English grammar correctly.
Most  nouns in English are countable:
   He  has two homes, one in London and one in Spain.
   The  beer cost six pounds.
   I’ve  never seen Sarah travel with less than two suitcases.
The verbs 'let', 'make, 'have' and 'get' cause a considerable amount of confusion. Here is an overview of their functions and meanings when speaking about allowing, forcing, giving responsibility and convincing people to do things.
'let+person+verb'
   Here  'let' is used to mean allow
My  dad lets me drive his car.
   Will  your boss let you leave early tomorrow?
   My  sister doesn't let us speak about her divorce.
To understand how to use 'who', 'whom' and 'whose' you first have to understand the difference between subjects, objects and possessives.
The  subject does the action:
   He likes football.
   She goes to university.
   They enjoy travelling. 
'Were to' is used in the present to place emphasis on the improbability of the condition. It shows that something is highly unlikely or unthinkable. This form is used in the 'if-clause'.
If  he were to be my boss, I think I would quit the next day.
   If  I were to have no friends, I would be terribly lonely.
   If  she were to be right about that, we’d never hear the end of it.