A:excuse
B:plane
C:evening
D:left
— Excuse me, have you seen _______ umbrella here?— Yes. Is it _______ beautiful blue one? I saw it here just now.
下列食物链中,表述正确的是 ( )
在国际单位制中电磁场理论相关物理量单位符号写法不正确的是( )