从岸边看水中的鱼,看到“鱼”的位置与实验位置不同。下列模型能解释此现象是 ( )
A:
B:
C:
D:
判断下列晶体类型。
①SiI4:熔点120.5℃,沸点287.4℃,易水解:____。
②硼:熔点2300℃,沸点2550℃,硬度大:____。
③硒:熔点217℃,沸点685℃,溶于氯仿:____。
④锑:熔点630.74℃,沸点1750℃,导电:____。
生物分类等级中,介于纲和科之间的分类单位是
完形填空。Dear friend, I am 1 American school girl. My name is Alice Green. I am twelve. I 2 two brothers. My brothers and I 3 all at school. We go to school 4 Monday 5 Friday. We 6 have classes on 7and Sunday. We don't go to school on weekends. My father and my mother are teachers. They say China is great. I like 8, and I can sing a lot of songs. My brother and I like baseball and basketball. 9do you like? Let's10friends. Please write soon.Yours,Alice Green