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8 When a sentence refers to two or more events which happened in the past, it is helpful to think in terms of ‘foreground’ and ‘background’, as in these two English examples: ‘While I was doing the dishes [continuous back- ground], I heard [foreground] the doorbell’; ‘I saw [foreground] Juve a couple of times when I was [continuous background] in Turin’. In Italian, in cases like these, the imperfect expresses the continuous ‘background’ action against which the ‘foreground’ action is seen to occur: 

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* Note that mentre  (while), in the past, is always followed by the imperfect. 

If the two events happened at the same time and lasted for the same length of time, then both verbs are in the imperfect: 

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