(What) is known to us all is that China is a developing country (belonging to) the Third World.A:As;belong toB:It;belongs toC:What;belonging toD:That;belonging to为什么选C?

问题描述:

(What) is known to us all is that China is a developing country (belonging to) the Third World.
A:As;belong toB:It;belongs toC:What;belonging toD:That;belonging to为什么选C?

is known to us all前缺成份,缺主语所以只能用what。belonging to做定语与修饰词country是主动关系

第一个是主语从句,.what is known to us all 是主语部分,后面的is是谓语,主语从句中在选项里只能选what作为引导词。
第二个it is known to us that···应该是一种固定句型,意为“我们都知道···”it做句子的形式主语,that China is a developing country是真正主语。
至于为什么不用as,是因为as有自己的搭配,应该是As is known to us,China is a developing country 。是定语从句
这个考察的知识点不同,而且不同的小词有自己的搭配,要注意区分。
希望能帮到你*^^~

第一个是主语从句,.what is known to us all 是主语部分,后面的is是……that……,抛开它,句子也能成立,句子改成China is a developing

用what衬托出中国对于一个发展中的国家的一个楷椽
还有就是belonging to这个有个进行时的缘故。意思就是说现在也还是belonging to the third world
如果不用belonging那么就会变成过去式那么就会是belonged

因为
(What) is known to us all 是主语从句中的主语
(belonging to) the Third World 是 developing country 的后置定语