什么叫无线电波的辐射？
参考答案：
把天线电流的能量转换成电磁波能量的过程叫辐射。
_____ the earth to be flat, many feared that Columbus would fall off the edge of the earth. [ ]
A. Having believed
B. Believing
C. Believed
D. Being believed
重症肌无力常合并以下哪种疾病（）？
A.小细胞肺癌
B.甲状腺功能亢进
C.多发性肌炎
D.胸腺增生或胸腺瘤
E.系统性红斑狼疮
