斑疹伤寒立克次体由何种虫媒传播()。 A.蚊 B.蝗 C.蚤 D.虱 E.螨 发布时间:2017-08-21 19:06 │ 来源:www.tikuol.com 题型:单项选择题 B1型题 问题: 斑疹伤寒立克次体由何种虫媒传播()。A.蚊B.蝗C.蚤D.虱E.螨
题型:单项选择题 B1型题 对获得的化学实验信息进行分析和处理,是科学探究的重要步骤,下列关于实验信息的分析和处理正确的是( )A.测得某溶液的pH<7,证明该溶液是碱性溶液B.某固体中加入稀盐酸,产生无色气体,证明该物质中一定含有碳酸根离子C.实验测得某无色气体燃烧的产物中含有水,说明这种气体一定是氢气D.做如下图三个对照实验探究铁生锈的条件,发现图(1)中铁钉生锈最严重,证明铁在氧气和水同时存在时最易生锈 查看答案
题型:单项选择题 B1型题 Temperature changes during the day or night can be great 6 small. This depends partly 7 how many clouds are in the sky. 8 there are many clouds during the night, they act like tile covers on your bed. They blanket the earth and keep the air from losing much of 9 heat. The temperature usually does not drop much during such a night. When there are many clouds during 10 day, some of the sun's energy will not reach the earth. The temperature usually does not rise much on such a day. 查看答案