河北省2022-2023学年六校联盟高二年级下学期期末联考(232824D)英语考试试卷

河北省2022-2023学年六校联盟高二年级下学期期末联考(232824D)英语考试试卷正在持续更新，目前金太阳答案为大家整理了相关试题及答案，供大家查缺补漏，高效提升成绩。

D At any given moment,about seven microliters of tears are present in each of our eyes-about a tenth of a drop of water. You might think of them as nothing more than salty water,but they deliver oxygen and nutrients to our eyes,removing waste, serving as the first line of defense against pathogens(病原体) and helping to heal injuries. Tears also contain traces of the various chemicals originally present in blood,some of which serve as markers of illness-glu- cose(葡萄糖)，for example,which can signal diabetes.That'sa primary reason doctors order blood tests.But it also means that physicians can look for indicators of illness by looking at your tears.