patanjali.purpose wrote:
IMO the elephant desended on its own (there is no external agency making elephant to descend - atleast its not clear from sentence) and therefore we cannot convert into passive. This Avik has rightly pointed is "inTRANSITIVE VERB".
In passive we require a logical subject (generally denoted by "BY" - sometime this may NOT be present in sentence but will be obvious). Therefore even though "IS DESCENED" takes the passive construction of (TO BE + PAST PARTICIPLE), it is NOT passive as there is no logical subject of IS DESCEND.
IMO Ron intends to say "is descended from" and "is a descendant of" are same in meaning NOT MATHEMATICALLY, as IS DESCENDED FROM (TO BE + PAST PARTICIPLE+PREP) while IS A DESCENDANT OF (TO BE + NOUN)
"is descended" is indeed passive. The significance of passive is that the gramatical subject is not doing the action. Here we can't say that the elephant descended on its own. Logical subject (by X) is generally deleted as we are not concerned who is the doer of the action, but on whome the action is being done.
The police caught the thief. - in this sentence the main topic is "the police" ( subject actually defines the topic).
The thief was caught. - in this sentence the main topic is "the thief" ( subject actually defines the topic). When this sentence is written the doer of the action is not the main consideration for the author.
here, logically we can say -
The elephant descended into the river.
The elephant descended from the aquatic animal - here it implies that the elephant is doing the action of its own. How can an elephant do that ?
"evolved" is different from the verb "descended".
1. "Evolved" is always a intransitive verb, but "descended" can act both as transitive and Intransitive verb.
He quickly descended the stairs. - here its an transitive verb.
2. "evolved" - the subject is the implied object. So when we use this kind of verb, it is implied that the subject is not doing the action. E.g : happened, rolled.... So even the sentence being active, the subject do not perform the action.
The tsunami happened in X.
The ball rolled down the stairs.
The elephant evolved from the aquatic animal - this is active, but correct. When we are using "evolved", it is always taken into consideration that "elephant" cannot do the action of evolving of its own. So in the second part of the sentence - "trunk originally evolved" is correct even being active.
patanjali.purpose wrote:D vs E
HAS DESCENDED implies Descending started sometime in past and still continues - is elephant STILL EVOLVING FROM acquatic animal? We cannot say from sentence - the original sentence says its a one time activity by using IS DESCENDENT.
I can also infer this sentence 2 WAYS:
1) "elephant HAS EVOLVED FROOM ANIMAL ..AND ..TRUCK HAS EVOLVED.." or
2) "elephant HAS EVOLVED FROM ANIMAL ..AND ..TRUCK EVOLVED.."
(1) We can misinterpret that both elephant and trunk CONTINUES TO EVOLVE while in (2) we can interpret that elephant CONTINUES TO EVOLVE but trunk ALREADY EVOLVED. Two different interpretation
D can be eliminated based on active voice - "has descended", which is again active.
