良性溃疡的征象是（）
A．跳跃征
B．狭颈征
C．充盈缺损
D．间位结肠
E．空回肠换位征
参考答案：B
He said _____. [ ]
A. that I am a teacher
B.I was a teacher
C. that he is a teacher
D. he was a teacher
炼钢炉渣作用是什么？
