There are thirty sentences in this section. Beneath each sentence there are four words or phrases marked A, B, C and D. Choose one word or phrase that best completes the sentence.
Mark your answers on your answer sheet.
Bit by bit, a child makes the necessary changes to make his language _______.

A．Noise is a major problem; most people recognize its importance.
B．Although noise can be annoying, it is not a major problem.
C．Noise is a major problem and has not yet been recognized as such.
D．Noise is a major problem about which nothing can be don

A．shippers will be charged less without a rival railroad
B．there will soon be only one railroad company nationwide
C．overcharged shippers are unlikely to appeal for rate relief
D．a government board ensures fair play in railway business