Seenfromthehill,thecityismorebeautiful.Seeingfromthehill,youcanseethewholecity.一个现在分词,一个过去分词,中文意思有什么不同,现在和过去词在用法上有什么区别?还有那个独立主格我老是搞不清

Question

Seen from the hill,the city is more beautiful.
Seeing from the hill,you can see the whole city.
一个现在分词,一个过去分词,中文意思有什么不同,现在和过去词在用法上有什么区别?
还有那个独立主格我老是搞不清楚.比如什么时候用现在,什么时候用过去,还有那个It being 的形式怎么用.
All flights______because of the storm,they decide to take the train.
A.having cancelled B.were ancelled C.have been cancelled D.cancelled
1._____,we decided to leave at once,as we didn't want to risk missing the bus.
A.As it being pretty late B.It being pretty late
C.It was being pretty late D.Being pretty late
2.All things____,the planned trip had to be called off.
A.considered B.be considered
C.considering D.having considered
3.____tired after a hard work,she fell into bed and went straight to sleep.
A.Felt B,Feeling C.Being felt D.To feel
4.Classes____,the students left for home without delay.
A.were over B.being over C.are over D.over
5.The plane crashed,its bombs _____as it hit the ground.
A.exploded B,were exploded C.exploding D.were exploding
有一个小问题,"因为这另加的主格是独立于主句主语的",请问"独立于主句主语"是什么意思,

Answer 1

一、现在分词和过去分词依旧是动词,凡是动词,都需要一个行为的支配者,这种行为支配者在语法上称为逻辑主语.由于你所提出的两个句子的逻辑主语不同,因此也就有了使用现在分词和过去分词的不同,具体分析如下：
1.Seen from the hill,the city is more beautiful 一句中,分词的逻辑主语是 the city,也就是说“城市”是被人看到的,所以要用过去分词表示.事实上,这个句子也可以用下面的从句表示：
When the it (the sity) is Seen from the hill,the city is more beautiful.（当这个城市[被]从山上看的时候,它显得更加美丽) .
过去分词短语就是由 When the it is Seen from the hill 省略了从句中的连词 when 和与主句主语重复的主语 it 以及被动语态的助动词 is 后,构成的时间状语.
2.Seeing from the hill,you can see the whole city 一句中,分词的逻辑主语是 you,也就是说 seeing 这个动作是 you 执行的.我们同样可以把它变成状语从句：
When you see from the hill,you can see the whole city.（当你从山上看下去的时候,你可以看到这个城市）
现在分词 seeing 就是这个从句去掉连词 when 主语 you 后,由原从句中谓语动词 see 变来的.
二、关于独立主格结构
所谓的独立主格结构指的是在上述的分词前另外加了一个由主格充当的逻辑主语,因为这另加的主格是独立于主句主语的,因此称作独立主格.如:
* The city seen from the hill,you can see the whole of it.(从山上看这个城市,你就能够看到它的全貌.)
其中的 The city 就是独立的主格,与后面的 seen 一起构成独立主格结构.
* You seeing from the hill,the city is more beautiful.(你要是从山上看,这个城市就更加美丽.)
其中的 you 就是独立的主格,与后面的 seing 一起构成独立主格结构.
三、补充问题
选择 D.cancelled
解析：
1.All flights cancelled because of the storm 是独立主格结构,其中 flights 是逻辑主语,又由于航班是使被取消的,因此用过去分词,相当于原因状语从句 Since all flights cancelled because of the storm （既然所有的航班都由于暴风雨被取消）.
2.其它选项
A.having cancelled 是现在分词短语,航班不可能是取消这动作的行为者.
B.were ancelled 属于谓语动词,一是没有连词与后面的句子发生关系,二是过去时态与后面句子的 decide 在时间上接不上茬.
C.have been cancelled 也属于谓语动词,但是必须改为从句 since all flights have been cancelled because of the storm 才能成立.
.