用异丙酸沉淀法提取获得DNA大小为（）用甲酰胺解聚法获得DNA大小

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问题配伍题 B1型题

用异丙酸沉淀法提取获得DNA大小为（）
用甲酰胺解聚法获得DNA大小为（）
用盐酸胍裂解细胞获得DNA大小为（）
用酚提取法获得DNA大小为（）

A.100～150kD

B.150～200kD

C.80kD

D.20～50kD

E.>200kD

答案

参考答案：E,A,D,E

填空题

读短文，用所给动词的适当形式填空。

English is one of the most important subjects in middle schools. Almost everyone 1_____ (know) that we

should learn English well, but few of us know how 2_____ (learn) it well. Karl Marx has set a good example

for us. He once 3_____ (say), "When one 4_____ (learn) a foreign language, he must use the foreign language."

In this way, he could use several languages. As the saying goes, "Practice makes perfect." When we learn

English, we should read more, speak more, listen to English from time to time and practice 5_____ (write)

every day. Don't be afraid of making mistakes. Only in this way can we learn it well.

多项选择题

下列( )税率属于比例税率。

A．城镇土地使用税

B．房产税

C．耕地占用税

D．营业税

E．城市维护建设税