单项选择题

Attempts to make artificial organs fail because______.

A．it is difficult to make artificial organs as natural as body organs
B．it is difficult to imitate the human world
C．the production process is complicated
D．the production is limited by nature

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热门试题

单项选择题

Which of the following is NOT a limitation of organ transplantation

A．The organ donor must be young enough.
B．The organ donor must be healthy enough.
C．The organ donated must deserve transplanting.
D．The organ donated must be removed from one body.

单项选择题

Lottery winners may not be happy______.

A．if they quit their job
B．if they move to a splendid house
C．if they spend a lot of money
D．if they are away from others