It said the country's confirmed H7N9 cases were isolated and there has been no of human-to-human transmission.
A. mark
B. symbol
C. sign
D. signal
网友回答
A. mark
B. symbol
(答案→)C. sign
D. signal
解析：考查名词辨析：A. mark记号B.symbol 象征C.sign迹象D.signal信号，句意：据说这个国家的确认H7N9病例被隔离,没有任何迹象表明人际间的传播。选C。