He left home ______a cold morning, and I heard that he was coming back _____ the late afternoon.

A．in; on

B．on; on

C．in; in

D．on; in

用ICP-AES法测定水中金属元素时，如果质控样品的测定值超出允许范围，需要用标准溶液重新调整仪器，然后再继续测定。