One possibility is the variable behavior of the sun．Astronomers at one research station have studied the hot spots and ‘cold’ spots (that is, the relatively less hot spots)on the sun．As the sun rotates(使旋转)，every 27．5 days，it presents hotter or colder faces to the earth，and different aspects to different parts of the earth．This seems to have a considerable effect on the distribution of the earth atmospheric pressure，and consequently on wind circulation．The sun is also changeable over a long term：its heat output goes up and down in cycles，the latest trend being downward．

　　‘

　　Scientists are now finding shared relations between models of solar weather interactions and the actual climate over many thousands of years，including the last ice Age．The problem is that the models are predicting that the world should be entering a new Ice Age and it is not．One way of solving this theoretical difficulty is to assume a delay of thousands of years while the solar effects overcome the inertia(惯性)of the earth‘s climate．If this is right, the warming effect of carbon dioxide might thus be serving as a useful opposed balance to the sun’s fading heat．

　　46．It can be concluded that a concentration of carbon dioxide in the atmosphere would

　　．

　　A．mean a warming-up in the Arctic

　　B．raise the temperature of the earth’s surface

【2017届山西省大同县高三英语一轮阅读理解训练（3）及答案】相关文章：

★ 安徽省淮南市2014高考英语一轮单项选择及文章训练（14）及答案

★ 贵州省贵阳市2014高考英语（新人教版）一轮阅读训练（15）附答案

★ 安徽省淮南市2014高考英语一轮单项选择及文章训练（20）及答案

★ 浙江省湖州市2014高考英语阅读理解一轮（暑假）精炼（9）含答案

★ 山西省永济市涑北中学高三英语总复习：美文欣赏（2）（Unconditional Love）

★ 浙江省湖州市2014高考英语阅读理解一轮（暑假）精炼（3）含答案

★ 盘点最新2016高考二轮复习英语阅读理解的八种能力

★ 浙江省湖州市2014高考英语阅读理解一轮（暑假）精炼（18）含答案

★ 2014高考英语（新人教版）一轮基础训练（20）A、B卷（附答案或解析）

★ 河南省三门峡市2014高考英语一轮（暑假）基础训练（4）附答案