你可以把 There is known to be…视为一种句型。这样用的There is known to be…句式可以看作是there be（有）与be known（被知道）的复合形式或混搭形式，其意为“据了解有……”“据说有……”“人们知道有……”“大家都知道有……”等。又如：

There is known to be an engine fault. 据了解发动机有故障。

There are known to be thousands of snakes on the island. 据了解，那座岛上有成千上万条蛇。

There are known to be thousands of different species of beetles. 据说有成千上万种不同的甲虫。

顺便给出以下类似的用法及句式：

1. There appears to be…

There appears to be…句式是there be（有）与appear（似乎）搭配而成的混搭形式，其意为“似乎有……”“好像有……”。如：

There appears to be a mistake. 似乎有一个错误。

There appears to be a problem with the oil pressure. 看来是油压出了问题。

类似的还有：There seems to be…（似乎有……）。如：

There seems to be something wrong with me. 我似乎有点不对劲。

There seems to be every reason to believe that business will get better. 看来完全有理由相信生意会转好。

注：there seems to be…结构中的to be有时也可以省略。如：

There seemed (to be) nobody about, so I went in. 附近似乎没有人，因此我就走了进去。

2. There is expected to be…

There is expected to be…句式是there be（有）与be expected（被预计）的混搭形式，其意为“预计有……”“估计有……”。如：

There is expected to be a severe frost tonight. 预计今晚会有严重的霜冻。

There is expected to be an announcement about the project next week. 预计下星期将宣布一件关于这项工程的事。

3. There is said to be…

There is said to be…句式是there be（有）与be said（被说，据说）的混搭形式，其意为“据说有……”。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 is said to be a lack of harmony within the government. 据说政府内部有分歧。

4. There is believed to be…

There is believed to be…句式是there be（有）与be believed（被相信，据信，据说）的混搭形式，其意为“据信有……”“据说有……”。如：

There is believed to be a number of wounded on both sides. 据信双方都有一些人受伤。

There are believed to be over two hundred monkeys living in the valley. 据说山谷里生活着200多只猴子。

5. There is supposed to be…

There is supposed to be…句式是there be（有）与be supposed to（应该）的混搭形式，其意为“应该有……”。如：

There is supposed to be a train at 12:37. 12点37分应该有一班火车。

There is supposed to be some trouble when he hears the news. 他听到这消息后应该有些麻烦。

6. There is sure to be…

There is sure to be…句式是there be（有）与be sure（肯定）的混搭形式，其意为“肯定有……”“准有……”。如：

There’s sure to be a place for him somewhere. 在什么地方准有他的容身之地。

There is sure to be trouble when she gets his letter. 当她收到他的信时，肯定会有麻烦。

7. There happens to be…

There happens to be…句式是there be（有）与happen（碰巧）的混搭形式，其意为“碰巧有……”。如：

There happened to be a man walking by. 当时恰好有一个人从旁经过。

There happened to be a severe drought that year. 那年碰巧出现了大旱。

8. There used to be…

There used to be…句式是there be（有）与used to（曾经有）的混搭形式，其意为“曾经有……”“过去有……”。如：

There are fewer applicants this year than there used to be. 今年的申请者比往年少。

There used to be a small park just around the corner. 以前在那个拐角处曾有一个小公园。