I have worked with him for some time and have found that he is than Jim.A. more efficient

问题补充：

I have worked with him for some time and have found that he is than Jim.

A. more efficiently a worker

B. a more efficient worker

C. more an efficient worker

D. a worker more efficient

答案：

A. more efficiently a worker

B. a more efficient worker

C. more an efficient worker

D. a worker more efficient

解析：B

解析考查比较结构中的名词位置。此处符合“a/an＋比较级＋名词单数＋than”句型。