题干
根据上下文补上所缺的单词的ing形式，使短文完整
(write do cook clean wash answer listen draw read work)
Everybody is very busy. Grandpa is____a letter. Grandma is____a book. Dad is ____in the study. Mom is ____dinner in the kitchen. Brother is ____ to music. Sister is____ the room. I am ____ pictures. Uncle is ____the phone. Aunt is ____ clothes. Cousin is____ homework.
答案(点此获取答案解析）
writing,reading,working,cooking,listening,cleaning,drawing,answering,washing,doing
N2+CO2+2H2O，则框内物质的化学式是（ ）