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题库 / Prep2007E2-SC-83
The number of plant and animal species that humans are known to have forced to extinction in the last half millennium is over 800.
humans are known to have forced to extinction
humans are known as having forced to become extinct
humans are known for forcing to become extinct
are known that humans forced to become extinct
are known as having been forced to extinction by humans
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Ron：
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'.
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