During my second year of nursing school，our teacher gave us a test.I was a hard﹣working student and I did well1all the subjects.I finished the questions 2until I read the last one，"What is the first name of  the woman3cleans the school？"

    Of course this was only a joke.I saw4 cleaning woman every day.She is short and about 60 years old.

    She has dark hair.5 how would I know her name？I have never talked with her before.In fact，I've never even thought about6to her!I stared at my paper.7 guilty I felt! Finally，I handed in my paper，but the last question 8.

    Before the class ended，one student asked the teacher9the last question would count into our grade.

    "Of course，"the teacher said，"In your life，you will meet10 people.It's important for you 11 them.They deserve（值得）your attention and care，even if all you do is just 12 hello."I'll never forget that lesson.Everyone deserves our attention and we13 try to get to know all the people who work and live around us.That was14 lesson of my life.Later that day，I 15that the cleaning woman's name was Dorothy.

中央谷地位于海岸山脉和内华达山脉（海拔1800~3000米）之间（如下图），原为印第安人的聚居地。1848年归属美国。持续7年的淘金热使该地区人口急增，城市迅速发展。1849年以后，中央谷地农牧业迅速发展，建成灌溉网。1869年横贯美国大陆的铁路通车，将本地区与全国其他地区连接起来，中央谷地渐渐成为美国重要的水果、蔬菜、牛奶、蛋、肉产区。据此完成下列各题。

眼是形成视觉的结构．眼球是人眼的主要结构，在眼球结构中，位于眼球最前方的是一层透明的薄膜，称为____ ；可以调节瞳孔大小的是____ ；像双凸透镜，有弹性，可以根据物体远近的不同而改变曲度的是____ ；富含血管，具有营养作用的是____ ；具有感光作用，形成物像的是____ ．