在无缝钢管的端部通常标有印记，其主要包括钢管的（）
A.牌号
B.产品标准号
C.供方印记或注册商标
D.产品规格
参考答案：A, B, C, D
—Is that the laundry? I have some clothes ________.
—Leave them in your room,please,and we're going to fetch them soon.
[ ]
A. to wash
B. to be washed
C. washed
D. washing
简述腰神经丛的组成。
