I didn’t know when he _____ back. He said he would call me when he _____ home.

A．would come, got

B．came, got

C．will come, gets

D．came, would get

入冬以后，妈妈开车送小明上学，小明发现车内的“固体清新剂”一天天变小，这是因为“固体清新剂”发生了______现象（填物态变化名称），这个过程要______热量．