--What do you think of cloning?--No doubt it’s a great invention. But it may have some s

问题补充：

--What do you think of cloning?

--No doubt it’s a great invention. But , it may have some side effects.

A. if not properly handling

B. if properly not handled

C. if not properly handled

D. if properly not handling

答案：

A. if not properly handling

B. if properly not handled

(答案→)C. if not properly handled

D. if properly not handling

解析：考查分词的用法。题意，如不能正确处理，克隆可能有副作用。修饰分词否定式的副词应置于not之后，排除B,D项；分词做状语的时候，如句子主语是分词动作的承受者，应该使用过去分词，排除A项。故C项正确。