A:-1,+ ∞)
B:-1,0)
C:( - ∞ ,-1
D:(- ∞ ,-1 ∪ (0 ,+ ∞)
①状态和颜色的变化;②发光发热;③生成新物质;④气体的放出;⑤能量的变化.
Cathy was born blind(天生是盲的), so she has __________ seen our beautiful world.
____×4<21
____×4<10
日常生活中用到的下列物质,其中属于纯净物的是