— What are you doing? — [ ]
A. I write a letter.
B. I am cooking.
C. I am tired.
答案:B
下列骨肿瘤属于恶性的是().
A.骨髓瘤
B.骨巨细胞瘤
C.骨样骨瘤
D.骨软骨瘤
E.骨瘤
季节折扣