下列关于红细胞的叙述，正确的是 [ ]
A．红细胞含有细胞核
B．红细胞的形状是圆球形的
C．红细胞可运输氧
D．在人体血液中，红细胞的数量最少
答案：C
— Can you remember this park? We _____ here.
— Sure. But now I _____ in that swimming pool. [ ]
A. are used to take a walk, am used to swim
B. are used to taking a walk, am used to swimming
C. used to take a walk, used to swim
D. used to take a walk, am used to swimming
适合防水混凝土的养护方法是（）
A、蒸养法
B、电热发养护
C、自然养护
D、都适合
