还是prep2012，关于不定式平行的省略问题

风行稚

Prep2012-Pack1-SC-052 VSC002367 Medium

The industrial pollutants known as were first manufactured in 1929 and were used as coolants for electrical equipment in Europe and North America the 19705, when studies showed that the compounds had entered the food chain and were harmful to some animals. A

A. that the compounds had entered the food chain and were harmful to some animals 由此可见同主语时主谓宾和主系表是可以平行的？

B. the compounds to have entered the food chain and be harmful to some animals    be前需加to，因为前面是现在完成时的不定式，所以后面也必须要是不定式？

C. the entry of the compounds into the food chain as harmful to some animals    as改成to be，as做连词不能只加单个的形容词

D. the entry of the compounds into the food chain and its harmfulness to animals   its不对，harmfulness很笨拙

E. the compounds entering into the food chain and harming some animals    into多余，这句子说得好像研究和研究的结果一起发生似的

风行稚

  挖坟……我已经彻底弃坑了

小雨嘀嗒着

我觉得是因为不定时没有完成时态~~不知道对不对