51.The historical events of that period are arranged ()
A.in alphabetical order
52.They like to take a vacation ()
C.once a year
53.”What is Todger?” “He is () .”
A.a poet and novelist
54.”How did you pay the workers ” “As a rule ,they are paid () “
B.by the hour
55.”The DMZ extends about two hundred kilometers ()
A.from east to west