2021届四川省部分地区高三英语一模试卷汇编：七选五专题

四川省部分地区2021届高三一模英语解析版试卷分类汇编 七选五专题 四川省巴中市2021届高三一诊英语试题- 二、七选五 Can you remember a morning when you’ve woken up to the ring of your alarm clock and wished you could stay in bed? You haven’t slept well, your eyes are bleary(模糊的) and your hair is a mess. Worse, you can’t stop yawning(打哈欠). But why, exactly, do we yawn?____16____ . One theory is that when we are bored or tired, we just don’t breathe as deeply as we usually do. ____17____Therefore, yawning helps us bring more oxygen into the blood and move more carbon dioxide out of the blood. Yawning, then, would be an action that we can’t really control to help us control our oxygen and carbon dioxide levels. Sounds good, but other studies have shown that breathing more oxygen does not make us yawn less.____18____. Hmmm. Now what? ___19___. Stretching and yawing may be a way to exercise muscle and joints, increase heart rate, and feel more awake. Other people believe that yawning is a protective reflex to redistribute he oil-like substance called surfactant that helps keep lungs from drying up and caving in. So, if we didn’t yawn, according to this theory, taking a deep breath would become harder and harder-and that would not be good! But there is one idea about yawing that everyone knows to be true:____20____. If you yawn in class, you’ll probably notice a few other people will start yawing, too. Even thinking about yawn-ing can get you yawning How many times have you yawned while reading this article? We hope not many! A．It seems to spread. B．Yawning seems to be common. C．No one knows for sure, but there are many theories. D．Another theory is that yawning stretches he lung and lung tissue. E．Similarly, breathing more carbon dioxide does not increase yawning. F．This theory indices yawning like a deep breath, helps us feel fresh. G．As this theory goes, our bodies take in less oxygen because our breathing has slowed. 四川省凉山州2021届高中毕业班第一次诊断性检测英语试题 五、七选五 Some people make you feel comfortable