【单选题】

By the time I finished high school, my interest in animals had grown, and enrolled at a university to study biology. I learned soon enough that studying animals (56) this level was not in the animals best (57) . I remember one midterm exam in (58) each student was handed a large, fleshly-killed frog and (59) to dissect (解剖) and mark a set of body parts. I looked at the (60) flog in front of me and was saddened that her life was (61) away for such a slight (62) .

A、year later, in the same lab (63) I dissected the flog, I performed a small act of animal (64) . We were (65) on fruit flies, and it was time to record the distribution of characteristics in their next generation. Flies were (66) in small plastic bottles.Counting the number of flies with white or red eyes required first exposing them to ether (乙醚) (67) . they could not move. The flies were then spread onto a piece of white paper (68) and counteD、When the data collection was (69) , the flies had no further use, and our instructions were to (70) them into a small glass dish of oil at the center of each desk, which was to be their final resting (71) .
Once may little pile of flies had been counted, I pushed them off the edge of the paper.As we recorded our data, I kept one eye (72) them. Within minutes the pile was humming (嗡嗡叫) as tiny legs and wings beat their way out of the ether fog. I was extremely excited as they (73) flight. That was my first (74) in refusing to conduct scientific research that treated nonhuman life in a(n) (75) way.
A．being examined
B．to be examined
C．being operated
D．to be operated