搜题请搜索小程序“爱下问搜题”
问题 选择题

为了认识酶作用的特性，以体积分数为3%的H2O2溶液为反应底物进行的一组实验结果见下表。通过分析实验结果，从表中可得到的实验结论是

①从化学本质看，酶是蛋白质或RNA ②从催化活性看，酶变性后就失去活性 ③从催化底物范围看，酶有专一性 ④从催化反应效率看，酶有高效性

[ ]

A．①②

B．②③

C．②④

D．②③④

答案

答案：C

选择题

“夫珠玉金银，饥不可食，寒不可衣”，但人们还是喜欢金银。这表明金银作为货币 [ ]

A．从起源看是和商品同时产生的

B．从作用看是财富的唯一象征

C．从本质看是固定充当一般等价物的商品

D．从职能看具有价值尺度、贮藏手段两种基本职能

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句型转换

根据各小题Ａ句的意思完成Ｂ句，使两句的意思基本相同。每空限填一个单词。

小题1:A: His friend didn't know what he should do.

B: His friend didn't know      do.

小题2:A: What was wrong with the old man？

B: What             the old man？

小题3:A: He found it was not easy to sleep.

B: He found       to sleep.

小题4:A: He went to bed at twelve last night.

B: He go to bed twelve last night

小题5:A: She was worried and her friend was worried, too.

B: She was worried and            her friend.

小题6:A: She always makes me happier when I’m unhappy.

B: She always      me    when I’m unhappy.
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