问题补充：
Almost all of his time experiments, he has no time to visit his parents.
A. devoted to do
B. devoted to doing
C. devoting to doing
D. is devoted to doing
答案：
A. devoted to do
(答案→)B. devoted to doing
C. devoting to doing
D. is devoted to doing
解析：devoted to后接名词或者动名词,致力于……过去分词做他的时间和devote有动宾关系，故用被动语态，此处省略be动词，故选B。
