She made a silly mistake because she hadn’t kept heron her work.A. headB. heartC. brainD.

问题补充：

She made a silly mistake because she hadn’t kept heron her work.

A. head

B. heart

C. brain

D. mind

答案：

A. head

B. heart

C. brain

(答案→)D. mind

解析：keep one’s mind on sth.专心于……。类似结构的近义短语为：put one’s heart into专心致志于……，该句意为：她因工作不用心，而犯了一个愚蠢的错误。