20.     

The hognose snake puts on an impressive bluff, hissing and rearing back, broadens the flesh behind its head the way a cobra does, feigning repeated strikes, but, having no dangerous fangs and no venom, eventually, if its pursuer is not cowed by the performance, will fall over and play dead.

 (A) broadens the flesh behind its head the way a cobra does, feigning repeated strikes, but, having no dangerous fangs and no venom,

(B) broadens the flesh behind its head the way a cobra does and feigns repeated strikes, but with no dangerous fangs and no venom,

(C) broadening the flesh behind its head the way a cobra does and feigning repeated strikes, but it has no dangerous fangs and no venom, and

(D) broadening the flesh behind its head the way a cobra does and feigns repeated strikes, but with no dangerous fangs and no venom, and

A.     broadening the flesh behind its head the way a cobra does, feigning repeated strikes, but with no dangerous fangs and no venom, and 

原文大致意思：说蛇 puts on an impressive bluff，后面hissing了什么，broaden了什么，feigning了什么但是having no了什么（实在是看不懂具体内容，很正常，因为你又不是生物学家）

 题目分析：虽然读不懂具体内容，但是我们明显能读出原文蛇的一系列动作形成了并列，但是A用broadens显然和前面的hissing、后面的feigning不对应，杀。B和A犯的错误是类似的，杀。C用broadening和前后那几个动作还是比较对应的，留着。D的broadening和后面的feigns显然不对应，Ebut后面用了一个with引导的介词短语，而前面是个句子，显然也不对应，杀！此题虽然具体内容不懂，但是大的句子逻辑还是比较清楚的！