Following are two examples:
|Would you like to meet Wednesday, August 2nd?|
|No, how about Friday at 2.||2pm, Friday 4 August|
|How about the 3rd week of August?|
|Let's see, Tuesday sounds good.||Tuesday of the 3rd week in August|
In the first example, the day specified in the first utterance is used as the frame of reference. In the second example, the beginning day of the interval representing the 3rd week of August is used as the frame of reference.
Note that tense can influence the choice of whether to calculate a forward or backward time from a frame of reference , but this is not accounted for because there is not much tense variation in the CMU corpus on which the algorithm was developed. However, errors can occur because backward calculations are not covered. For example, one might mention ``Friday'' and then ``Thursday,'' intending ``Thursday'' to be calculated as the day before that Friday, rather than the Thursday of the week following that Friday. We are investigating creating a new anaphoric relation to cover these cases.