下列物质的用途,主要由化学性质决定的是( )
A:石墨用作电极
B:活性炭除去异味
C:干冰用于人工降雨
D:镁粉用于照明弹
— Could I speak to Betty, please?
— ______. She's coming in a minute.
“爆竹声中一岁除,春风送暖入屠苏。千门万户瞳瞳日,总把新桃换旧符。”王安石这首诗描述了宋代哪一节日的气氛( )