Dear Moderators and friends

The number of plant and animal species that humans are known to have forced to extinction in the last half millennium is over 800.

a.
b. humans are known as having forced to become extinct.
c. humans are known for forcing to become extinct.
d. are known that humans forced to become extinct.
e. are known as having forced to extinction by humans.

de wrong due SV error
bc wrong due to redundant "become extinct"?
OA A

Thanks
KH[/u]

'to become extinct' does seem, to my eyes, more awkward and wordy than 'to extinction', but there are other issues in choices b and c.

choice b:
biggest problem = incorrect idiom: 'known as having forced'
known as is used with nouns: al capone was known as a gangster rather than as a tax cheat, but he was ultimately imprisoned only on charges of tax evasion.

with verbs, you have to use 'known to infinitive' or 'known for gerund'.

choice c:
fatal change of meaning.
this sentence implies that we are currently 'forcing [these species] to become extinct', a meaning that not only differs from the original but also borders on absurdity.
the original meaning, which we're not allowed to change, is that humans have forced the species into extinction at some point in the last 500 years, not that humans are doing so currently.
analogies:
the island's natives are known for stealing tourists' money, passports, and jewelry. --> these things go on today
the island's natives are known to have stolen tourists' money, passports, and jewelry. --> not necessarily still happening, but it has happened at some point

hope that makes sense.

You the best.
KH

Hi Ron,

Nice explanation... but I have a small question
I am confused with the usage of having, to have - verbals for "have" basically...

cant understand how can we have this construction

'known for present participle'.

if for is a preposition...then as its direct object I should have a noun... or can i use a present participle also...

and if i have a construction like... "knows as NOUN" ... then i should be able to place an infinitive or a gerund there..as they act as noun.....
i think .. i am terribly confused...pls help

Thanks.

ah yes, my mistake, i meant 'gerund'. i have edited the post above to reflect this observation.

thank you.

(although certainly no harm has been done, as present participles and gerunds look the same; it's always nice to make a mistake that doesn't have any consequences)

Ron you are simply best