Used to (do)

    A. Study this example situation:

  Dennis stopped smoking two years ago. He doesn't smoke any more.

  But he used to smoke.

  He used to smoke 40 cigarettes a day.

  'He used to smoke' = he smoked regularly for some time in the past, but he doesn't smoke now. He was a smoker, but now he isn't

    B. 'Something used to happen' = something happened regularly in the past but no longer happens:

  * I used to play tennis a lot but I don't play very often now.

  * Diane used to travel a lot. These days she doesn't go away so often.

  * 'Do you go to the cinema very often?' 'Not now, but I used to.' (= I used to go ...)

  We also use used to... for something that was true but is not true any more:

  * This building is now a furniture shop. It used to be a cinema.

  * I used to think he was unfriendly but now I realise he's a very nice person.

  * I've started drinking coffee recently. I never used to like it before.

  * Janet used to have very long hair when she was a child.

    C. 'I used to do something' is past. There is no present form. You cannot say 'I use to do'. To talk about the present, use the present simple (I do).

  Compare:

  past: he used to smoke  we used to live  there used to be

  present: he smokes  we live  there is

  * We used to live in a small village but now we live in London.

  * There used to be four cinemas in the town. Now there is only one.

    D. The normal question form is did (you) use to ...?:

  * Did you use to eat a lot of sweets when you were a child?

  The negative form is didn't use to ... (used not to ... is also possible)

  * I didn't use to like him. (or I used not to like him.)

    E. Compare I used to do and I was doing.

  * I used to watch TV a lot. (= I watched TV regularly in the past, but I no longer do this)

  * I was watching TV when the phone rang. (= I was in the middle of watching TV)

    F. Do not confuse I used to do and I am used to doing
  
   The structures and meanings are different:

  * I used to live alone. (= I lived alone in the past but I no longer live alone)

  * I am used to living alone. (= I live alone and I don't find it strange or new because I've been living alone for some time)