火焰原子吸收分光光度法测定气体污染源中铅时，样品预处理方法有两种：（）和（）。
参考答案：索氏提取法；酸煮法
I told them not everybody could run as fast as you did, ________?[ ]
A. could he
B. didn't I
C. didn't you
D. could they
E=5KG的SGT—30型地中衡的最小秤量值的刻度在（）上。
