After a short holiday, he himself once more to his studies.
A. applied
B. converted
C. engaged
D. exerted
网友回答
(答案→)A. applied
B. converted
C. engaged
D. exerted
解析： apply oneself to“致力于”。Apply one's mind to(专心于)。Apply to sb. for aid(向某人求援)。Apply a theory to practice(把理论应用于实践)。