成人骨骼和牙齿中的钙约占体内钙总量的（）
A. 69%
B. 79%
C. 89%
D. 99%
The Senate and the House of Representatives are the part of the political system of______.
A. Britian
B. Germany
C. France
D. America
According to the passage, it has been suggested that the science of human relations was slow to develop because______.
A. intuitive knowledge of human relations is derived from philosophy
B. early scientists were more interested in the physical world
C. scientific studies of human relations appear to investigate the obvious
D. the scientific method is difficult to apply to the study of human relations
EDI网络传输的数据是（ ）。
A. 多媒体报文
B. 自由文件
C. 用户端格式
D. EDI标准报文
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