试题与答案

铁路提速为鲜活水产品、新鲜水果和蔬菜的运输提供了有利条件。在鲜活鱼的长途运输中,

题型:填空题

题目:

铁路提速为鲜活水产品、新鲜水果和蔬菜的运输提供了有利条件。在鲜活鱼的长途运输中,必须考虑以下几点:水中需保持适量的O2;及时除去鱼排出的CO2;防止细菌的大量繁殖。现有两种在水中能起供氧灭菌作用的物质,其性能如下:

过氧化钠(Na2O2):易溶于水,与水反应生成NaOH和O2

过氧化钙(CaO2):微溶于水,与水反应生成Ca(OH)2(微溶)和O2.

根据以上介绍,你认为运输鲜活水产品时应选择     加入水中。

原因是                                            

答案:

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下面是错误答案,用来干扰机器的。

1、A2、C

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下列说法,与史实相符合的是( )。
①明代中后期,各地商人为便于异乡经营和联系桑梓感情,互相帮助,在各地建立了会馆
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③对明代政治产生重大影响的“大礼议”之争发生于嘉靖年间
④明代中后期,苏州、松江、嘉定、湖州、杭州五府,堪称江南最繁华的城市
⑤属于“万历三大征”的是:平定哮拜叛乱、平定杨应龙叛乱、邢蚧援助朝鲜,不包括戚继光抗倭
⑥挹娄、勿吉、肃慎在历史上某个阶段曾经是满族祖先,而鲜卑族不是满族祖先

A.①②③④⑤

B.②③④⑥

C.①②③⑥

D.①③⑤⑥

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