(2013·东北三校二模)—In case anyone ________ come in my absence, tell him I will be back soon.

—Sure, I will.

A．would

B．should

C．will

D．shall

2，4-二硝基氟苯分光光度法测定空气中异氰酸甲酯，空气中的异氰酸甲酯在二甲基亚砜—盐酸吸收液中水解为甲胺，甲胺遇2，4-二硝基氟苯转化为黄色的2，4-二硝基苯基甲胺。该黄色络合物用四氯甲烷萃取后，用分光光度法测定。