The US federal government has released 252 applications so far, fields including education and health care.
A. covered
B. to cover
C. covering
D. having covering
网友回答
A. covered
B. to cover
(答案→)C. covering
D. having covering
解析：句意：美国联邦政府到目前为止已经推出了 252个申请，涉及的领域包括教育和健康护理。这里是定语，修饰applications ，applications和cover是主动关系，用现在分词做定语，所以选C。