I was about to walk over to Tom's seat when he ______ and left.

A．set up

B．got up

C．put up

D．came up

生活饮用水及其水源中的铝规定了用铬天青S分光光度法测定。该法最低检测质量为0.2μg，若取25mL水样，则最低检测浓度为下列何值（）。

A.0.008mg/L

B.0.005mg/L

C.0.010mg/L

D.0.002mg/L

E.0.02mg/L