We all feel it is Jack that for their son’s bad performance at school.A. are to blameB. i

问题补充：

We all feel it is Jack that for their son’s bad performance at school.

A. are to blame

B. is to be blamed

C. are to be blamed

D. is to blame

答案：

A. are to blame

B. is to be blamed

C. are to be blamed

(答案→)D. is to blame

解析：考查固定词组和主谓一致。固定词组：be to blame应受责备；本题是强调句型，句子的主语是jack，故使用单数形式。故D正确。