A special research team from the local medical center【C1】______experiments on completely b

A special research team from the local medical center【C1】______experiments on completely blind babies. The babies to be tested on lived at home with their mothers of families. The research workers would visit the babies and closely【C2】______the development of their senses and behavior. every two weeks. In most【C3】______, the research workers tested the responses of the blind babies to different stimuli (刺激) common in the family environment. Generally speaking,a【C4】______baby would react with smiles and laughter to tickling(瘙痒) ,to the voice of a relative,and to hugging(拥抱)from his family. His reactions were swift.【C5】______, most of the blind babies, according to the experiments, responded to stimuli impassively. In fact,they were indifferent to【C6】______sound. But【C7】______some special situations, some of them were able to【C8】______ to the sound of their mothers with a smile. Usually, their response was very【C9】______ The tests were done about nine months;they【C10】______ when the blind babies were one month old and ended when they were ten months old.

【C1】

A．carried

B．did

C．finished

D．took

请帮忙给出正确答案和分析，谢谢！