下列哪项是平衡阀的图例（）。
A.A
B.B
C.C
D.D
参考答案：A
—Where is your brother now, Alan?
—_____. [ ]
A. He is working in the school
B. He likes singing
C. His favorite animals are dolphins
D. He usually gets up at 7:00
为什么酿酒用玉米必须脱胚？
