Grade 4 Grammar Lesson 17 Negation
It is the verbs that make a sentence negative.
Verbs take not or its contraction n’t to change themselves into negative.
For a simple present verb without -s ending, use do not.
For a simple present verb with – s ending, use does not + verb without – s.
For a simple past verb, use did not + verb in the simple form.
Contracted forms are also possible.