An example of this might be where you started work and found that your eyesight was affected by computer screens but had not noticed this problem before you started work.
Enghraifft bosibl o hyn yw eich bod wedi dechrau gweithio ac wedi canfod bod sgriniau cyfrifiadurol yn effeithio ar eich golwg ond nad oeddech wedi sylwi ar y broblem hon cyn i chi ddechrau gweithio.