D

题目分析：句意：在线调查结果显示，预计房价不可能再涨了。It做形式主语，如果用as,则应该是As is expected, housing prices can’t go up any more.也可以是：According to the online survey, housing prices can’t go up any more，which is expected.或者What is expected is that housing prices can’t go up any more.故选D。

考点: 考查代词的用法。