8. Which sentence from paragraph 1 contains one of the author's main claims?
A "Probably you have to go down several coal-mines before you can get much grasp of
the processes that are going on round you."
B "This is chiefly because the mere effort of getting from place to place makes it difficult
to notice anything else."
C "In some ways it is even disappointing, or at least is unlike what you have expected."
D "You get into the cage, which is a steel box about as wide as a telephone box and two
or three times as long."