Suppose there are 2 chords within a measure of 4 beats. The first chord sounds from the first beat of the measure until the middle (or first half part) of the second beat. The other chord starts to be used from the middle of the second beat until the end of the measure as shown in the figure below:
My question is: Is it wrong to say that the first chord lasts from the beginning of the measure until the middle of the second beat or would it be better to say that the first chord is used from the beginning of the measure until the middle of the second beat when the other chord will start to be used? I'm very confused about this. I'm not sure if I can say that the chord lasts, remains, is used for a part of the measure, or even sounds from the beginning until a given part of the measure. Could you help me please?