问题
选择题
She often goes to work __________ .
A．by a underground
B．by underground
C．by the underground
D．take the underground
答案
答案：B
题目分析：句意：她经常坐地铁上班。短语by underground坐地铁，中间不需要冠词；或者可表述为She often takes the ground to work.结合语境故选B。