适于尿沉渣检查的标本为（）
A.首次晨尿
B.随机尿
C.3h尿
D.24h尿
E.餐后尿
参考答案：A
We have ______ our position on the issue! Whatever happens, we won't change it. [ ]
A. explained
B. concluded
C. introduced
D. clarified
