There is known to be a big problem.

這個句子怎么樣理解？

There is known to be…可以當作一種句型來看待嗎？

你可以把 There is known to be…視為一種句型。如此用的Thereis known to be…句式可以看作是there be（有）與be known（被了解）的復合形式或混搭形式，其意為“據悉有……”“據了解有……”“大家了解有……”“大伙都了解有……”等。又如：

There isknown to be an engine fault. 據悉發動機有問題。

There areknown to be thousands of snakes on the island. 據悉，那座島上有成千上萬條蛇。

There areknown to be thousands of different species of beetles. 據了解有成千上萬種不一樣的甲蟲。

順便給出以下類似的使用方法及句式：

1. Thereappears to be…

Thereappears to be…句式是there be（有）與appear（好像）搭配而成的混搭形式，其意為“好像有……”“仿佛有……”。如：

Thereappears to be a mistake. 好像有一個錯誤。

Thereappears to be a problem with the oil pressure. 看來是油壓出了問題。

類似的還有：There seems to be…（好像有……）。如：

Thereseems to be something wrong with me. 我好像有點不對勁。

There seemsto be every reason to believe that business will get better. 看來完全有理由相信買賣會轉好。

注：there seems to be…結構中的to be有時也可以省略。如：

Thereseemed nobody about, so I went in. 附近好像無人，因此我就走了進來。

2. Thereis expected to be…

There is expected to be…句式是there be（有）與beexpected（被預計）的混搭形式，其意為“預計有……”“估計有……”。如：

There is expected to be a severe frost tonight.預計今晚會有緊急的霜凍。

There isexpected to be an announcement about the project next week. 預計下星期將宣布一件關于這項工程的事。

3. Thereis said to be…

There issaid to be…句式是there be（有）與be said（被說，據了解）的混搭形式，其意為“據了解有……”。如：

There issaid to be plenty of oil off our coast. 據了解國內沿海有很多的石油。

There is said to be alack of harmony within the government. 據了解政府內部有分歧。

4. There isbelieved to be…

There is believed to be…句式是there be（有）與be believed（被相信，據信，據了解）的混搭形式，其意為“據信有……”“據了解有……”。如：

There is believed tobe a number of wounded on both sides. 據信雙方都有一些人受傷。

There are believed tobe over two hundred monkeys living in the valley. 據了解山谷里生活著200多只猴子。

5. Thereis supposed to be…

There issupposed to be…句式是there be（有）與be supposed to（應該）的混搭形式，其意為“應該有……”。如：

There issupposed to be a train at 12:37. 12點37分應該有一班火車。

There issupposed to be some trouble when he hears the news. 他聽到這消息后應該有的麻煩。

6. Thereis sure to be…

There issure to be…句式是there be（有）與be sure（一定）的混搭形式，其意為“一定有……”“準有……”。如：

There’ssure to be a place for him somewhere. 在什么地方準有他的容身之地。

There issure to be trouble when she gets his letter. 當她收到他的信時，一定會有麻煩。

7. Therehappens to be…

Therehappens to be…句式是there be（有）與happen（碰巧）的混搭形式，其意為“碰巧有……”。如：

Therehappened to be a man walking by. 當時恰好有一個人從旁經過。

Therehappened to be a severe drought that year. 那年碰巧出現了大旱。

8. Thereused to be…

There usedto be…句式是there be（有）與used to（過去有）的混搭形式，其意為“過去有……”“過去有……”。如：

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

There usedto be a small park just around the corner. 以前在那個拐角處曾有一個小公園。