A.It is an encyclopedia about London streets.
B.It is an exam would-be cabbies must pass.
C.It is a navigation between the landmarks.
D.It is a license for the cabby profession.
A.the expense of spending luxurious holidays in Spain
B.the waste of time to remembering London streets
C.the efforts of grasping the transportation knowledge
D.the hardship of living as a London taxi driver