When I went in they were in a heated discussion .A. absorbB. absorbedC. absorbingD. bei

问题补充：

When I went in , they were in a heated discussion .

A. absorb

B. absorbed

C. absorbing

D. being absorbed

答案：

A. absorb

(答案→)B. absorbed

C. absorbing

D. being absorbed

解析：考查固定词组，be absorbed in意思“全神贯注于”，句子意思“当我进来时，它们全神贯注于激烈的讨论”，所以选B