His mum and grandma ____ Chinese.[ ]
A. is
B. are
C. was
答案:B
皮肤基底细胞癌为()
A.来源于皮肤或基底细胞,发展迅速,转移早
B.伴有色素沉着时,呈黑色,变为恶性黑色素瘤
C.对放射线敏感,可放疗,也可手术切除
D.经常发生血液和淋巴转移
E.为高度恶性肿瘤
简述信息技术外包的优缺点。