USED TO, DIDN'T USE TO

IMPORTANT: Used not to is called "formal style" by Michael Swan (a British writer) in Practical English Usage, 2e (Oxford University Press, 1995). He lists "didn't use to" as an informal style.

Positive sentences	I used to smoke 20 cigarettes a day. I used to eat loads of junk food.
Negative sentences	I didn't use to do any exercise. I didn't use to swim very well.
All pronouns take used to / didn't use to	I You She He It We They	used to / didn't use to	eat a lot of sweets. eat meat. live in the city. have long hair.

Used to and didn't use to are only used to talk about past habits. There is no present form. To talk about present habits we can use the present simple. When using these structures there are often two parts to the sentence, something about the past and something about the present, for example:

I used to drive to work but now I go by car.
I didn't use to like coffee but I love it now.


EXERCISES

http://www.agendaweb.org/verbs/to-be-used-to.html

https://elt.oup.com/student/solutions1stedition/int_unit_page/unit2/grammar/exercise2?cc=cz&selLanguage=cs

http://www.englishgrammar.org/exercise-8/

http://www.tolearnenglish.com/exercises/exercise-english-2/exercise-english-17482.php