A oes gan y plentyn beswch parhaus? Mae hyn yn golygu tagu am fwy nag awr, neu 3 cyfnod o dagu mewn 24 awr (os ydynt yn tagu fel arfer, gall fod yn waeth na’r arfer). / Does the child have a persistent or continuous cough? This means coughing a lot for more than an hour, or 3 or more coughing episodes in 24 hours (if they usually have a cough, it may be worse than usual) *