Present and past simple : Negative

FORM (past simple)
Subject + did not (didn’t) + base verb

EXAMPLE 
They didn’t have tyres before.

CAREFUL!
– Do is used as the only auxiliary in the present simple negative, and the past simple negative.
– It can also be used as a main verb.

EXAMPLE
Used as an auxiliary in negations in simple present : I don’t do the washing up.
Used as an auxiliary in negations in simple past : I didn’t do the washing up.

Used as a main verb in the simple present : I do not do the washing up.
Used as a main verb in the simple past : I did the washing up.