初级卫生保健的伦理意义有()
A.使全人类都健康
B.使全人类都文明
C.使全人类都幸福
D.是社会公正的体现
E.是社会和谐的组成部分
参考答案:D
Tom is a promising student. I am sure that with his________effort, he will make a very successful scientist.
A.usual
B.constant
C.content
D.normal
如图所示,为使电杆稳固,在杆上加了两根拉线CA和CB,若每根拉线的拉力都是300 N,两根拉线间的夹角为60°,求拉线拉力的合力大小和方向。