The idea for the new machine came to Mr．Baker ________ to his invention recently．

A.while devoting

B.while devoted

C.while he was devoted

D.while devoting himself．

答案及解析： C

解析：

while后主语及助动词不能省略，因为两句主语不一致。如主语一致，则：Mr Baker thought of the idea for the new machine (B / D) to his invention recently.