Electronic cigarettes started out being marketed to smokers as a way to help them quit. Now e­cigarettes have been mainstreamed.Scientists expect to see more information coming out about e­cigarettes and their health effects.

　　E­cigarettes don't fill the lungs with harmful smoke，but that doesn't make them a healthy alternative to regular cigarettes.When you use an e­cigarette，you're still putting nicotine—which is absorbed through your lungs—into your system. In addition to being an addictive drug，researchers at the University of Utah used some animals to conduct a study to prove the toxic effects of nicotine.Later it was once even used as a chemical drug to kill some insects in agriculture.

　　Nicotine affects your brain，nervous system，and heart.It raises the blood pressure and the heart rate. The larger an amount of nicotine，the more a person's blood pressure and heart rate go up.This can cause an arrhythmia(心律失常)．In rare casesely again.Over time，nicotine use can lead to serious medical problems，including heart disease，blood clots，and stomach diseases.

　　1．The underlined word“toxic”in Paragraph 5 is closest in meaning to________．B．poisonous ficial

　　D．curableout to be practical for smokers.

　　D．Because it is convenient for smokers to carry.

　　3．When using an e­cigarette，________．otine into lungs

【2017届高考英语一轮选修模块复习训练：选修7 Unit 2《Robots》（新人教版含解析）】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（16）及答案

★ 【浙江专用】2014届高考英语一轮复习课时作业(三十七)选修8Unit 2《Cloning》

★ 【北师大版】2014届高考英语一轮复习指导课时作业：Unit 11 A卷 Word版含解析

★ 2014届高考英语一轮复习必修1参考答案（外研版）

★ 2017届高考英语二轮复习大题冲关秘籍语法填空：创新押题（含解析）

★ 【人教版】2014届高考英语一轮复习指导考点针对练：必修1 unit4《Earthquakes》

★ 安徽省淮南市2014高考英语一轮单项选择及文章训练（11）及答案

★ 【浙江专用】2014届高考英语一轮复习课时作业(三十八)选修8Unit 3《Inventors and inventions》

★ 2014高考英语（新人教版）一轮基础训练（16）A、B卷（附答案或解析）

★ 2014届高考英语一轮复习课时作业(二十二)必修4Module 4《Great Scientists》（外研版）