关于如图下列说法正解的是( )
A:甲是静脉
B:丙是动脉
C:乙是毛细血管
D:甲一定流动脉血
如图中“□”表示人体的一些体液和排泄物的正常pH值范围,据此判断其中酸性最强的是( )
下列加线词语,解释不正确的一项( )
A. white B. orange C. pencil D. pen E. green
Hi, I'm Lucy. I have a pencil box. It's ____ I have a ____ It's black. I have an eraser. It's ____ I have a ____ It's red. I have a crayon. It's____