题目：
Only after hearing about a potential job promotion did she begin
working ____________ than the other employees.
(A) efficiently
(B) more efficiently
(C) efficient
(D) more efficient
疑问：答案(B) 我选(D) 选D的原因是念起来顺而且形容词也常出现
不懂这题为什么选副词,请问如何判别,麻烦大大赐教\