prep 2#83

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.

(A) humans are known to have forced to extinction

(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 been forced to extinction by humans

Be known to do sth 是什么意思，人们被知道的迫使已经灭绝的物种超过了800，怎么觉得好别扭呀，如果要是选A的话，是不是也应该改成：

Humans know to have forced to extinction 呀？这样顺一些。

be known to do 广为人知（我只见过这种用法吧，没见过主动地）

be known as/for 以。。著名

我用中文配合着说吧

人们所知道的。。。物种的灭绝数量。。超过的了800

(humans are known to have forced to) extinction of the number(主语） of species is over 800.

请问这道题是选A么