To their great fear they found in the heaviest snowfall they had ever had.A. they were

问题补充：

To their great fear, they found in the heaviest snowfall they had ever had.

A. they were catching

B. themselves caught

C. they had caught

D. themselves catching

答案：

A. they were catching

(答案→)B. themselves caught

C. they had caught

D. themselves catching

解析：本题考查非谓语动词的用法。根据句型结构以及句子对语态的要求，此处用过去分词短语作宾语补足语，构成find oneself done，表示“发现自己被……”；另外be caught in也是固定用法，表示“遭遇”。