对于未穿救生衣的落水者来说,最适宜的漂浮姿态应是()
A、蛙泳
B、自由泳
C、仰泳
参考答案:C
He is said___________a book on the history of Chinese tone bridge , but I don’t know if he has finished it.
A. to have written B. to be writing C . having writing D writing
下面基于关系数据库系统的,以数据处理为主的传统的数据库应用所具有的特征的叙述,比较全面的是 Ⅰ.结构统一 Ⅱ.面向记录 Ⅲ.数据项小 Ⅳ.原子字段
A.Ⅰ,Ⅱ和Ⅲ
B.Ⅱ,Ⅲ和Ⅳ
C.Ⅰ,Ⅲ和Ⅳ
D.Ⅰ,Ⅱ,Ⅲ和Ⅳ