While the children are(3)………...., so the custom goes, Father Christmas or Santa Claus, comes (but also to children who have been good).Đoạn văn13/30While the children are(3)………...., so the custom goes, Father Christmas or Santa Claus, comes (but also to children who have been good).sleep asleep sleeping slept Giải thíchC là đáp án đúng