经肠道传播的肝炎病毒（）
A.HAV
B.HDV
C.HCV
D.HEV
E.HBV
参考答案：A, D
Having been attacked by terrorists, _____.
A．doctors cane to their rescue
B．the tall building collapsed
C．an emergency measure was taken
D．warnings were given to tourists
A．4：1
B．1：
C．2：1
D．：1
：1