语法与词汇  It is not uncommon for there _____ problems of communicationbetween the old and the young.
【正确答案】 D
【答案解析】句意：老年人和年轻人之间有代沟是很常见的事。本题考查的是介词＋ there be的用法。It is＋ adj.＋ for there to be，故答案选D项。