题目内容：
根据以下材料，回答题Then blacken the corresponding letter on the Answer Sheet．By the time I finished high school，my interest in animals had grown，and I enrolled at a university to study biology．I learned soon enough that studying animals56_________ this level was not inthe animals’best57_________．I remember one midterm exanl in58_________each student was handed a large，freshly—killed frog and59_________ to dissect(解剖)and mark a set of body parts．I looked at the
60_________frog in front of me and was saddened that her life was6l_________away for such a slight62_________
A year later．in the same lab63_________I dissected the frog．I performed a small act of animal64_________．We were 65_________0n fruit flies，and it was time to record the distribution of characteristics intheir next generation．Flies were66_________in small plastic bottles．Counting the number of flies withwhite or red eyes required first exposing them to ether(乙醚)67_________ they could not move．Theflies were then spread onto a piece of white paper68_________and counted．When the data collection was69_________，the flies had no further use，and our instructions were t0 70_________ them into a small glass dish of oil at the center of each desk，which was to be their final resting71_________．
Once my little pile of flies had been counted，I pushed them off the edge of the paper．As we recorded our data，I kept one eye72_________ them．Within minutes the pile was humming(嗡嗡叫)as tiny legs and wings beat their way out of the ether f09．1 was extremely excited as they73_________flight．That was my first74_________in refusing to conduct scientific research that treated nonhuman life in a(n)75_________way．
第56题答案是______ A．at
B．wim
C．for
D．Off
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