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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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be known/believed to do sth，被认为作了某事，被动里可以+to
force sb to do sth，强迫某人作某事；force sb to sth，强迫某人进入某种状态，如：Health forced him into early retirement. 从语法上来说，to是介词，+doing或+名词都可以
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