好发于40岁以上的“恶性骨肿瘤”是（）
A.骨脂肪肉瘤
B.扁骨的纤维肉瘤
C.原发性软骨肉瘤
D.尤文肉瘤
E.骨肉瘤
参考答案：B
系统是由相互联系和相互作用的诸要素构成的统一整体。系统的基本特征是( )
①整体性 ②客观性 ③有序性 ④内部结构的优化趋向
A．①②
B．②④
C．①③④
D．②③
People Who Moved China, hosted by CCTV, honours the people ______ the valuable contributions
should be remembered by every Chinese. [ ]
A. whose
B. of whom
C. that
D. of which
