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问题 选择题

下列关于噬菌体侵染细菌实验的相关叙述中，不正确的是[ ]

A．该实验证明了子代噬菌体的各种性状是通过DNA遗传的

B．侵染过程的“合成”阶段，噬菌体DNA作为模板，而原料、ATP、酶、场所等条件均由细菌提供

C．为确认蛋白质外壳是否注入细菌体内，可用35S标记噬菌体

D．若用32P对噬菌体双链DNA标记，再转入普通培养基中让其连续复制n次，则含32P的DNA应占子代DNA总数的1/2n

答案

答案：D

选择题

1965年日本的水俣病的病因是

A．汞污染

B．铅污染

C．DDT污染

D．二氧化硫污染
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单项选择题

When we want to tell other people what we think, we can do it with the help of words. We can also do it in many other ways, too. Sometimes we move our heads up and down when we want to say "yes", and we shake our heads when we want to say "no " Some people can’t hear or speak. They talk with the help of gestures(手势). People from other countries often have to do it if they don’t know your language.
Here is a story. An American was once having his holiday in Italy, but he could not speak Italian. One day he went to a restaurant and sat down at a table. When the waiter came, the American opened his mouth, put his fingers in it and took them out again. In this way he wanted to say "Bring me something to eat". The waiter soon brought him a cup of tea. The American shook his head and the waiter understood that he didn’t want tea. So he took it away and brought him a glass of milk. The American shook his head again. He was very hungry now and looked sad. He was just going to leave the restaurant when another man came in. When this man saw the waiter, he put his hands on his stomach (胃). In a few minutes there was a large plate of bread and meat on the table in front of him.

If people want to say ______, they may shake their heads.

A．"no"

B．"yes"

C．"words"

D．"OK"
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