It is human activities on the earth that are to global warming.
A. be blamed for
B. blame for
C. take charge of
D. be responsible with
网友回答
A. be blamed for
(答案→)B. blame for
C. take charge of
D. be responsible with
解析：考查固定结构。Be to blame for应受责备，为……负责。所以选B。