问题
单项选择题
Tourists often surprised at ______ so many flat and good roads in the mountainous regions.
A) there are C) there to be
B) there being D) there were
答案
参考答案：B
解析：介词后面接名词或动名词做宾语。there is(或are)的动名词形式是there being，故B为正确答案。at后不能接从句，所以A和D都错。there to be是there be的不定式形式，不能做介词的宾语，故也错误。句意：看到山区有如此多的平坦大道，旅客感到很吃惊。