英语问题(请说明理由!)

a 不定式表将来 DOING表的是正在做

选A
there to be 和there being 结构可用作主语、宾语、或状语
I 主语
1、有for引导，则用there to be。
It’s a great pity for there to be much trouble in the class.
太遗憾了，这个班上有多方面的麻烦。
2、没有for引导，则用there being。
There being a public bus service is a great convenience to people..
公交车对人们十分方便。
II 宾语
1、介词宾语，用there being结构，而不用there to be。
What’s the chance of there being an election this year?
今年举行选举的可能性有多大？
2、动词宾语。
①跟动名词的动词后用there being。
常见的动词有：deny, appreciate, mind, imagine, admit,
②跟不定式的动词后用there to be。
常见的动词有：want, expect, hope, wish, like , hate, would like, prefer, mean, intend等。
She denied there being any misunderstanding between them.
她否认他们之间有任何误会。
Teachers don’t want there to be any students lagging behind.
老师不希望有任何学生掉队。
III 作状语
1、作独立主格结构，用there being.
There being nothing else to do, they went home.没有别的事做，他们回家了。
2、但若置于介词for之后，则用there to be，整个介词短语作程度状