dentist n.牙医;impossible adj.不可能的;pull out a tooth(动词结构)拔掉一颗牙;cotton wool 药棉;collect vt.收集;match box火柴盒;collection n.收集,收藏;grow v.成长,增长;in answer to one’s question作为对某人问题的回答;nod v.点头;make strange noises(动词结构)弄出奇怪的声响;meanwhile adv.与此同时;tongue n.舌头;be busy doing sth.忙着做某事;search out 动词短语)搜出;hole n.洞;remove vt.移开,去除;pull out the wrong tooth拔错牙