细胞破碎的主要方法有机械破碎法、物理破碎法、()、()。

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问题:

细胞破碎的主要方法有机械破碎法、物理破碎法、()、()。

考点:化学工程酶题库
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阅读答问 阅读下面的材料,然后根据材料内容回答问题。

     Police in America were looking for a thirteen-year-old boy, Ben. He was a middle school student. He was

lost last Friday night.

     Ben's mother went to bed early that evening because she had a bad cold. She thought Ben was spending

the night with his friend. However, Ben did not appear at the family lunch the next day. She became worried

and called the police.

     That evening, Ben left home to play baseball with two friends. They both said Ben went home after the

game. Some neighbors said to the police they saw a UFO flying over Ben's house that night. So they thought

Ben might be taken away by aliens.

     The police said they would not give up until they found him.

1. When was Ben lost?

    ______________________________________________________________

2. What did Ben do with his friends that evening?

   ______________________________________________________________

3. What might happen to Ben according to his neighbors?

    _______________________________________________________________

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下列实验操作的先后顺序合理的是[ ]

A.制取乙酸乙酯,应先将乙醇、乙酸混合,后加入到浓硫酸中

B.酸碱中和滴定中,应先将锥形瓶用待测液润洗,后加入一定体积的待测液

C.配制MgCl2溶液时,应先将MgCl2固体溶于浓盐酸中,后加水稀释

D.用分液漏斗滴加溶液,应先旋开分液漏斗的活塞,后打开漏斗上口的玻璃塞

题型:填空题

摄氏温度的字母符号是()。

A、K

B、J

C、S

D、℃

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何为永久变形?

题型:填空题

有关避孕套的使用,下列说法正确的是( )。

A.每次使用前选择适宜的型号,并检查有无破损
B.用双层避孕套可以增加避孕的效果
C.使用避孕套可以预防 * * 炎
D.用后洗净、晾干后可再用,以免浪费
E.使用避孕套,可以有效预防宫颈炎

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