—hat do you think of genetically modified food (转基因食品)? —We all think is careless some s

问题补充：

—hat do you think of genetically modified food (转基因食品)?

—We all think is careless some scientists to say it is safe before doing any experiment.

A. that, for

B. it, for

C. it, of

D. that, of

答案：

A. that, for

B. it, for

(答案→)C. it, of

D. that, of

解析：句意：-----你怎样认为转基因食品？-----我们都认为在没有进行任何试验之前科学家们说它很安全是他们的疏忽。这里是固定句式it be 形容词+of sb to do,当形容词可以描述某人的性格，品行时，用介词of而不用介词for，it在这里是形式主语，故选C。