There is a look on her face. She must have seen something horrible.A. frightB. frightenC.

问题补充：

There is a look on her face. She must have seen something horrible.

A. fright

B. frighten

C. frightened

D. frightening

答案：

A. fright

B. frighten

(答案→)C. frightened

D. frightening

解析：词性及词义辨析。Fright n惊吓；恐怖的东西；V使…害怕；frighten V使…害怕；frightened adj感到害怕的；frightening adj 令人害怕的；通常都用过去分词转化的形容词修饰人，用现在分词转换的形容词修饰事物，但是look(表情)是与人有关的，仍然要你管过去分词转换的形容词修饰，故本题C正确。