在杂交繁育体系中进行配合力测定，制定杂交方案的是品种场。
参考答案：错
—Sorry. I have taken your book by mistake.
— . [ ]
A. That's right
B. Not at all
C. All right
D. Never mind
钢轨焊接时，立焊焊条直径不得超过（）
A.2mm
B.6mm
C.5mm
D.4mm
