题目

–What’s  the problem ? -        . A.You should say thanks to her   B.That’s  a good idea C.My shirt is out of style       D.  You should call her up   答案：C 如图所示能够表示一个完整细胞周期的是 [　　] A．甲→乙 B．乙→甲 C．甲→甲 D．乙→乙