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问题 选择题

北京大学陈章良教授于20世纪90年代成功地把微生物的固氮基因整合到小麦的DNA分子中。该项生物技术属于[ ]

A．染色体变异

B．基因工程

C．细胞杂交

D．杂交育种

答案

答案：B

单项选择题

胼胝体发育不良首选的辅助检查方法是（）

A.头颅MRI检查

B.头颅CT检查

C.头颅超声波检查

D.头颅X线摄片

E.放射性核素检查
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听力题

单词拼写

The flying fox is not a fox at all. It is an extra large bat (蝙蝠) that has got a f   1    head, and that feeds on fruit i     2  of insects . Like all bats, flying foxes hang themselves by their toes when at rest, and t    3   in great groups when out flying. A group will l     4   in one place for y    5   . Sometimes several hundreds of them occupy (占据) a tree. As they return to the tree toward sunrise, they quarrel a    6    themselves and fight for the best places until long after daylight.

Flying foxes have b    7    once a year, giving birth to only one at a time. At first the mother has to c    8    the baby on her chest wherever she goes. Later she l    9    it hanging up, and brings back food for it to eat. Sometimes a baby bat falls down to the g    10   

and squeaks (尖叫) for help. Then the older ones swoop (俯冲) down and try to pick it up. If they f    11    to do so, it will die. Often hundreds of d    12    baby bats can be found lying on the ground at the foot of a tree.
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