早期胃癌诊断的最有效方法是()
A.B超
B.CT
C.X线钡餐造影
D.胃液分析
E.纤维胃镜
参考答案:E
大信号包络检波器中,若把二极管极性反接,是否起到检波作用?若能,则输出波形与原电路有什么不同?
— I don't know ____ makes him different from others.
— Honesty, I think. [ ]
A. how is it that
B. how it is that
C. what is it that
D. what it is that