9 鞭毛摆动和细胞分裂收缩环的作用主要分别涉及细胞骨架: A .微管与微丝 B .中间纤维与微管 C .中间纤维与微丝 D .都是微管 答案:A 解析: 鞭毛由微管组成,细胞分裂末期赤道部位会出现很多细微的纤维,形成收缩环,其成分是肌动蛋白丝,是微丝。5、Even the top students in our class didn' t work out
the problem. So it be
very difficult,
A.
need B.
must.
C. can t D. shouldn′t