题目

 ----- Why are they taking all the equipment away ? ------____________ , they are packing up to leave. A. The job was done                 B. The job has been done C. With the job done                 D. With the job doing 答案：C卵子是否受精的标志是 A．卵黄膜和透明带间出现两个极体       B．精卵相遇，发生顶体反应 C．精子接触透明带                     D．雌、雄原核形成