He devoted all the time his research .A. to doB. doingC. to doingD. did

问题补充：

He devoted all the time his research .

A. to do

B. doing

C. to doing

D. did

答案：

A. to do

B. doing

(答案→)C. to doing

D. did

解析：考查词组：devote all the time to doing，致力于做…,句意：他所有时间都致力于他的研究。选C。