过去分词与现在分词的判断 求NN详解

outsider0214

                                    If seriously mentally ill people do not receive medication, they can grow unable to support themselves, become irrational, and perhaps even threatening the safety of themselves or others.                                    
                                    

• Aand perhaps even threatening
• Band may even threaten
• Cand even a possible threat to
• Das well as possibly threatening as well
• Eas a possible threat to
  

这个题我可以算是凭语感做对的，觉得B比A要顺很多，但是，究竟为什么选B的过去分词，而非ing，我自己还没找到线索，求NN指点！！

victor198506

support, become, threaten三个动词关系是平行的,所以排除不用平行关系连词的E；然后平行关系的话三个动词的时态要一致，所以排除把threaten变成动名词和动词的A,C,D项

outsider0214

victor198506 发表于 2013-10-20 16:31
support, become, threaten三个动词关系是平行的,所以排除不用平行关系连词的E；然后平行关系的话三个动词 ...

谢谢victor，也就是说如果考虑平行的话，threaten是最好的选择