向高人求助：這個答案對嗎？

本人將參加今年國內首批MPAcc考試，在複習英語時遇到下面的題：
The originai building was erected  in 1710,  but this  structure  has  been largely transformed  and extended, the present  hotel(         )in 1910.
A: was completed             B: to have been completed
C: having  been completed    D: had been completed
答案：C
C答案是什麼時態？現在完成進行時？但我只見過have been completing 這種形式的。為什麼C是正確的？哪位高人給解答一下，謝了！！

it is 現在進行完成時.表示一個過去開始的並且現在仍在進行的動作.[:495:]

Ｉthink.

The originai building was erected in 1710, but this structure has been largely transformed and extended.(period) the present hotel( A)in 1910.

OR

The originai building was erected in 1710, but this structure has been largely transformed and extended,(comma)
( c)in 1910.

you can understand this with the following sentence.
Having been built in 1910, this structure has been largely transformed and extended.

我笨。。不懂呀！！[:457:] [:457:]

'C' is not chosen to be a predicate (謂語), but a present participle with perfect tense (現在分詞的完成形式) which is used to decorate "THE PRESENT HOTEL" as an adjective, meaning that some present work on the hotel has been completed recently. However, this is a compound scenario of two sentences with two parallel subjects, "THE ORIGINAL BUILDING" for one and "THE PRESENT HOTEL" for another. And "WAS ERECTED" is omitted from the 2nd sentence (this happens frequently to parallel subjects in English). Therefore, the whole sentence should look like as follows if it is completed with the missing part:

The originai building was erected in 1710, but this structure has been largely transformed and extended, the present hotel having been completed was erected in 1910.

Its Chinese translation is something like

這個樓房最初建於1710年，但它的大部分建築已被改造和擴展，已完成的現在這個旅館(的建築)則建於1910年。

By the way, "HAVING BEEN COMPLETED" is NOT the present perfect progressive tense (現在完成進行式). A present perfect progressive tense is as follows:

HAVE + BEEN + <RESENT PARTICIPLE> or HAS + BEEN + <RESENT PARTICIPLE>

such as "I HAVE BEEN TRYING TO WORK THIS OUT FOR WEEKS".

Sorry, I put a wrong subject for my comments above. Please ignore.

I deeply appreciate all of your explanations!