Principal White has been working in the school for about 20 years all his energy to teach

问题补充：

Principal White has been working in the school for about 20 years, all his energy to teaching and researching as well as the running of a healthy school．

A. devoted

B. devoting

C. to devote

D. and devote

答案：

A. devoted

(答案→)B. devoting

C. to devote

D. and devote

解析：后半句是一个伴随状语，现在分词作伴随状语表示主动关系，过去分词则表示被动关系，这里Principal White与devote 是主动关系。