This is when no affirmative is given to a sentence
It is usually realized by the introduction of ‘NOT’ to the statement
It is usually of the form NP (Noun Phrase) + V (Verb) + NOT + Obj (Object). For example:
The beautiful girl + is + not + mad
Article + adjective + noun (NP) + V + NOT
The sluggish boy is not healthy
The rumpled dresses were not ironed
I am a Nigerian, I am not in support of evil
The orange bus must not go to the farm today
NOTE:
In negative sentences, ‘do not’ (don’t) is added between a plural subject and verb, and ‘does not’ (doesn’t) is added between the singular subject and its verb
The -s form of a verb (has, likes, etc) is changed to its infinitive form without ‘to’ (live, like, etc.)
When a positive sentence has ‘shall’, ‘will’, ‘must’, ‘can’, ‘may’, between the verb and the subject, you do not have to add ‘do’ or ‘does’ to change it to its negative. For example:
Mercy must come with us – Mercy must not come with us