HBV是（）。
A.逆转录病毒
B.RNA病毒
C.呼吸道病毒
D.DNA病毒
E.肿瘤病毒
参考答案：D
依据灾害类型可将灭火救援预案划分为（）类。
A、4
B、5
C、6
D、7
Word has come ___ a 100-million-year-old dinosaur fossil was recently discovered on a mountain in Ningcheng County, Chifeng.
A．what
B．that
C．whether
D．when
