题目

Lori:  Good morning, Chuck. Are you here    66    (wait) for Professor Johnson? Chuck: Oh, yes. Good morning, Lori. The professor asked me to come here    67     (have) an interview. Do you know something about job as    68     teacher’s assistant? Lori:  Oh, yes. I know all about it    69     I have work experience in this field. Last year, I did it for a long time. Chuck: Really? How did you like    70    ? Lori:  Well, actually I think it was    71    (good) I had ever had at school. I was paid nine dollars an hour, which    72    细胞有丝分裂过程中，染色体、染色单体、DNA分子三者数量之比为1∶2∶2的时期是A．前期和中期B．中期和后期C．后期和末期D．前期和末期