A:B细胞
B:T细胞
C:吞噬细胞
D:造血干细胞
已知a和b一正一负,则aa+bb的值为( )
She looked at his fingers with wonder as they turned each page and suddenly reached for his hand. She was amazed by his and the softness and warmth of his skin.
小王的手指不慎划破出血,血液中与伤口止血和避免发炎有关的成分分别是( )