第一部分 必修1 Module 5　A Lesson in a Lab-（达标训练）【导学教程】2024旧教材老高考英语新编大一轮总复习（外研版）

[对应学生用书P383] Ⅰ.阅读理解 A (2022·南充模拟)In most countries，cigarette packages display images or characters that warn smokers of the increased risks of heart attacks，cancer and so on that accompany smoking. Many of these risks are associated with the 　inhalation　 of tobacco smoke through the mouth. But what is less often spotlighted is the effect smoking can have on the surface of the eyes. Smoking has been tied to age­related blindness and severe vision loss worldwide. But these changes occur in inner regions of the eyes. Now researchers have discovered how cigarette smoke and aerosols (气溶胶) from heated tobacco also kill cells in the eye's most exposed layer：the cornea (角膜). In the new study，published online in September，Otso and his colleagues reported that the compounds in cigarette smoke kills cells in a critical outer layer of corneal tissue called the corneal epithelium (角膜上皮). The researchers exposed lab­grown corneal epithelium cells to cigarette smoke extract—a solution (溶液) that contains most of the ingredients inhaled by cigarette smokers. They found that after 24 hours of exposure，more cells died in the containers compared with cells that were not exposed to smoke or tobacco. The sign indicated that exposing corneal cells to the tobacco products had caused the death of cell. It starts when compounds in the tobacco products make contact with the corneal cells，which leads ferritin (铁蛋白) inside the cells to start breaking down and releasing stored iron，Otso explains. Some of this iron stays together and reacts to produce chemicals that can harm cells. Normally the cells' repair systems can cope with these chemicals，but when too many accumulate，they damage fats in cells，triggering the cells to die. Because the study involved cell cultures rather than live human eyeballs，the researchers are not yet able to say how quickly smoking or heated tobacco products damage a person's corneas. The next steps will involve conducting animal experiments and testing the impact of