-- Tom, can you help me do some housework?
-- Sorry, mum. I to school.
A:go
B:goes
C:am going to go
D:going
46-6=____
58-50=____
70+10=____
50-20=____
①高尔基体形成的小泡与细胞膜融合
②吞噬细胞吞噬病菌
③小肠绒毛上皮细胞对Na+、K+的吸收
④核糖体中合成的蛋白质进入细胞核
⑤变形虫能出伪足.