帮忙讲解二道英语语法题

问题描述:

帮忙讲解二道英语语法题
1.After _______,these trains are capable of attaining a very high speed.
A.technically improving B.technically improved
C.being technically improved D.to be technically improved
请问为什么不选B,不是连词可以直接加分词,表被动么?
2.Everyone was warned of the danger of _______ at any time.
A.happened B.that might happen C.might happen D.happening
请问为什么不选D,分词可做后置的呀?

第一题:前面省略了主语these trains,火车的技术被提高,一用被动,而是介词after,后面只有名词后动名词.
第二题:每个人被警告危险随时可能发生,that在定语从句中做主语不能省.