____untreated,some small diseases can bring about serious problems.
问题描述：
____untreated,some small diseases can bring about serious problems.
A leaving B left C to leave Dto be left选哪个?
答
选B.Left untreated,some small diseases can bring about serious problems.被丢在一边不得到治疗的话,一些小的疾病会带来严重后果.本题考查非谓语动词.主语是some small diseases ,它和leave之间是被动的关系,所以...