单项选择题

Why is transition so difficult

A．Because transition requires money and time.
B．Because many manufacturers are unwilling to change their equipment.
C．Because research on new materials is very difficult.
D．Because it takes 10 years.

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热门试题

单项选择题

Why does the author mention genetic engineering and computer science

A．To compare them with the new materials.
B．To show the significance of the new materials on the future world.
C．To compare the new materials to them.
D．To explain his viewpoint.

单项选择题

According to the author, material science________.

A．was not attractive enough for its limited practice
B．was too dull to attract people' s attentions
C．was not well shaped to arouse people's interests
D．gave birth to new materials which could generate electric power