Past Simple - Did / Didn't

Did is generally used in English to indicate that the sentence or is in the interrogative form (that is, it is a question) or is a negative sentence (i.e. have a "not" in it). On the negative that "no" can be written or how did not or didn't (the short form). When used like this, we say that did only assists (help) in the formation of an interrogative or negative sentence. This means that we do not translate the word did (she's just a necessary accessory to keep things cute grammatical point of view).

That way, when did is used, the main verb (what communicates the central idea of the sentence) does not need to be written in the past. That is, it must retain its original shape (base form). To be clearer, compare the following sentences:

I didnt liked that (wrong)-I didn't like that (correct)

Did she went to the party? (wrong) – Did she go to the party? (correct)

They didnt studied very hard. (wrong) – They didn't study very hard. (correct)

Did you got a good grade? (wrong) – Did you get a good grade? (correct)

Did you got a good grade? (wrong) – Did you get a good grade? (correct)

Note the difference in featured verbs. In the correct way we use the word "did" and the main verb is always written in its normal form (he doesn't change according to the rules). See now how all this is to compare affirmative, negative sentences and interrogative:

She went to the party.  (Ela foi à festa.) [the main verb – go – was written in its shape in the past – went]

She didn't go to the party. (Ela não foi à festa.) [the main verb – go – kept their shape, because we didn ' t]

Did she go to the party?  (Ela foi à festa?) [the main verb – go – kept their shape, because we did]

Remember: only in affirmative sentences should use the forms of the irregular verbs or "-ed". In the interrogative or negative we did and the rest is still normal. If you want to learn more about regular and irregular verbs, read the Regular Verbs irregular verbs x tip.

Very briefly, this is the use of did and didn ' t in the Past Simple. But, before terminating the hint, see the sentences below:

She did a good job. (Affirmative)

Did she do a good job? (Interrogative)

She didn't do a good job. (Negative)