Before going abroad he devoted all he could his oral English.A. improveB. to improveC. im

问题补充：

Before going abroad he devoted all he could his oral English.

A. improve

B. to improve

C. improving

D. to improving

答案：

A. improve

B. to improve

C. improving

(答案→)D. to improving

解析：本题考查非谓语动词。句中考查短语devote … to …专心于。句意：出国之前，他尽他所能专心于他的口语。