在家庭发展史上，人类由群婚向个体婚过渡的主要形式是( )。
A．血缘家庭
B．普那路亚家庭
C．对偶家庭
D．核心家庭
参考答案：C
"大夫”在我国古代是（）
A Class C EPIRB（）.
A.is primarily designed for vessels operating up to 50 miles offshore or on foreign waters
B.transmits a signal that can be detected by satellite
C.must be manually activated
D.operates in the medium and low frequency bands
