the impact of the COVID-19 pandemic; it is unclear which effects are short term and which are longer term, making comparisons between years difficult
effaith y pandemig COVID-19; nid yw’n glir pa effeithiau sy’n rhai tymor byr a pha rai allai barhau dros y tymor hir, sy’n gwneud cymariaethau rhwng blynyddoedd yn anodd