To his surprise, Jack found his son as Santa Claus on Christmas Eve.
A. dressed
B. dressing
C. to dress
D. being dressed
网友回答
(答案→)A. dressed
B. dressing
C. to dress
D. being dressed
解析：句意：使他惊讶的是，在圣诞前夜他儿子装扮成圣诞老人。这里使用find+宾语+宾语补足语的结构，需要非谓语做宾语补足语，因为be dressed as“装扮成”，所以用过去分词做宾语补足语。选A。