伽玛刀治疗的主要缺点是()。
A.放射性脑损伤
B.可能使良性肿瘤发生恶变
C.对病灶大于3厘米者无效
D.价格昂贵
E.以上都不是
参考答案:A, B, C, D
He had no idea of what he should say in answer to the question, ______?
[ ]
A. did he
B. should he
C. didn't he
D. shouldn't he
以下属于风险转移策略的是()。
A.出口信贷保险
B.担保
C.备用信用证
D.市场对冲
E.自我对冲