小敏不慎将一块平行四边形玻璃打碎成如图的四块,为了能在商店配到一块与原来相同的平行四边形玻璃,他带了两块碎玻璃,其编号应该是( )
A:①,②
B:②,③
C:③,④
D:①,④
—What are you going to do after the exams to Senior High School?
—I am going to _____________ for vacation.
下列营养物质都能给人体提供能量的是( )
下列属于特异性免疫的是 ( )