My best friend is one of my classmates. Her name is Mary. Every day, we go to school together and go back home together. We often help each other and learn from each other in study. We have the same hobby-collecting stamps. She has many
计算:(﹣3)÷(﹣23)×(﹣49)
《生命与水》一文是一篇说明文,介绍了____,以及____。
①塞尔维亚参战具有民族解放性质
②战争爆发后意大利参加了同盟国集团作战
③战场主要集中在亚洲,先后有30多个国家卷入战争
④战场中首次使用了毒气弹、坦克新式杀伤性武器。1918年,同盟国战败宣告结束
+ + =12, =____