单选题 Human facial expressions differ from those of animals in the degree to which they can be______controlled and modified.

【正确答案】 A

【答案解析】[解析] 本题空格处是说被有意地控制和更改。deliberately的意思是“有意地”；deli cately的意思是“精致地”；definitely的意思是“确切地”；defectively的意思是“有缺陷地”，四个选项中只有A项符合题意。