题目

----What do you know the _____ of are the pig influenza in humans?    ---- usually similar to regular human seasonal influenza .    A. symptoms        B.sympathy            C.symbol           D.symptom 答案：A 解析: 考查名词词义辨析。句意：你知道人类感染猪流感后的症状吗？通常与患流行性感冒症状相似symptom症状符合句意;sympathy同情；symbol符号。从what are可以看出是复数名词。

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