Cohesion
Substitution
We can avoid repeating a word or expression that has been used before by substituting
  it with other words.
Substituting a noun or noun phrase with a pronoun
  -  I'd like a cup of coffee. Would you like one?
  
NOT: I'd like a cup of coffee. Would you
  like a cup of coffee?
 
  -  Look at this wonderful Spanish wine. I'm going
    to buy some.
NOT: Look at this wonderful Spanish wine.
    I'm going to buy this wine. 
 (Note that one replaces countable nouns, and
  some replaces uncountable nouns.)
  
    -  Jane's new sweater looks exactly like mine.
NOT: Jane's new sweater looks exactly like
    my new sweater. 
 Substituting a verb or verb phrase with do,
  does or did
  -  "Did you watch the news?" "Yes, I
    did."
    NOT: "Did you watch the news?" "Yes,
    I watched the news."
 
   
  -  "Does Peter come from Queensland?" "Yes,
    I think he does."
    NOT: "Does Peter come from Queensland?"
    "Yes, I think he comes from Queensland."
 
   
  -  "Do you often go to the movies?" "Yes,
    I do."
    NOT: "Do you often go to the movies?"
    "Yes, I often go to the movies."
 
 Substituting with so and not
 We substitute a clause, or an adjective or adverb, with so.
  
  -  Are you happy with the travel arrangements? If so,
    I'll tell the travel agency. 
	NOT: Are you happy with the travel arrangements?
    If you are happy with the travel arrangements, I'll tell the travel
    agency. 
  - It was very hot and remained so for days.
NOT: It was very hot and remained very
    hot for days.
 
We substitute a clause in the negative with not.
  -  Are you happy with the travel arrangements? If not,
    I'll tell the travel agency.
 
  -  Don't you like brown bread? If not, just tell
    me.
 
Instead of repeating information in a that clause,
  we can substitute the information with so. We do
  this with hope, suppose,
  imagine, believe,
  think, guess, be
  afraid and expect.
  -  "Is John a vegetarian?" "I believe
    so." 
    NOT: "Is John a vegetarian?" "I
    believe (that) John is a vegetarian."
 
  
  -  "Do you think he'll be late again?" "I
    suppose so."
    NOT: "Do you think he'll be late again?"
    "I suppose (that) he'll be late again."
 
 To put this in the negative, we use not.
  - "Do you think you will be late?" "I
    think not."
NOT: "Do you think you will be late?"
    "I don't think I will be late."
 
  - "I don't suppose he's coming for dinner."
    "No, I suppose not."
NOT: "I don't suppose he's coming for
    dinner." "No, I suppose he's not coming for dinner." 
 We can also use the verb in negative + so.
  - "Do you think you will be late?" "I
    don't think so."
 
  - "I don't suppose he's coming for dinner."
    "No, I don't suppose so."
 
 The verb in negative cannot be used with hope
  or be afraid.
  -  "Will he call later?" "I hope not."  
NOT: "Will he call later?" I don't
    hope so." 
  
  
-  "Can you come to dinner?" "I'm afraid
  not."
 NOT: "Can you come to dinner?"
      "I'm not afraid so."