另外还要注意 there be 句式与另一个被动结构混在一起使用的情况，即：

There+被动语态（be+过去分词）+to be+其他

例句如：

There is said to be plenty of oil off our coast. 据说我国沿海有大量的石油。

There are known to be thousands of different species of beetles. 据人们所知，甲虫有几千种。

There is expected to be an announcement about the proposed building next month.  预计会在下个月公布有关计划要建大楼的情况。

There is understood to be no suggestion of either doctor being involved in financial gain from the transaction. 据说没有迹象表明两名医生卷入从交易中获取现金收益。