单项选择题

Paper industry needed a new source of fiber in the early 1800s is because ______.

A．people wanted higher quality paper
B．paper made from rags deteriorated too quickly
C．wood pulp had become too expensive
D．the supply of rags was insufficient

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热门试题

单项选择题

The speaker mainly discusses ______.

A．the growth of the printing industry
B．the history of paper-making
C．the use of paper in the 19th century
D．the composition of wood fiber

单项选择题

Which of the following is NOT mentioned by the speaker

A．Diamond-producing rivers are located near the mountain sides.
B．Diamonds couldn’t be formed without great heat and pressure of the volcano.
C．Volcano explosions brought some diamonds up to the surface of the earth.
D．Explosions of the volcano can damage diamonds as well.