维生素B2的化学名称为()。
A. 生育酚
B. 硫胺素
C. 核黄素
D. 视黄醇
()can be regarded as a vessel restricted in her ability to maneuver.
Any aircraft designed to maneuver on the water
B. A vessel engaged in dredging,surveying or underwater operations
C. A vessel under sail provided that propelling machinery is not used
D. A small vessel sailing at night
到目前为止,我国总共已经推广了多少套广播体操?()
A. 17套
B. 18套
C. 19套
D. 20套
布莱克认为社会学模式关注的焦点是规则而不是社会结构。
A. 正确
B. 错误