问题补充：
There was a look on her face because a problem the little girl.
A. puzzled; puzzled; puzzled
B. puzzling; puzzling; puzzled
C. puzzled; puzzling; puzzled
D. puzzling; puzzled; puzzling
答案：
A. puzzled; puzzled; puzzled
(答案→)B. puzzling; puzzling; puzzled
C. puzzled; puzzling; puzzled
D. puzzling; puzzled; puzzling
解析：考查puzzle用法。Puzzling令人困惑的(常用来形容事物)；puzzled感到困惑的（常用来形容人）；有些与人有关的事物也用puzzled修饰；第三空是谓语动词，因为本句是过去时，所以使用过去式puzzled。句意：在他的脸上有一个困惑的表情，因为一个让人困惑的问题困扰着这个小女孩。故B正确。
