Ellen the eagle first suspected that she needed glasses the day that she swooped（猛扑） down out of the sky and grabbed a small lawn chair to carry back to her hungry children. When she arrived back at her nest, perched high atop a cliff, her oldest son said, somewhat sarcastically, "Great. Another lawn chair for breakfast. Just what we need." 

Her husband, Ed, was more forgiving. He gently picked up the lawn chair with his beak and moved it over to the flat, back section of the nest. Then he sat down in the lawn chair, folded his wings comfortably behind his head, and lay back. 

"Honey, you might want to go and have your eyes checked one of these days," Ed said. "It's easy enough to do, and only costs a mouse or two." 

"I've been meaning to get my eyes checked," replied Ellen, "but you know how it is. Every day it just seems that there are new mice to catch, new things to do for the nest, and new nature shows to be in." 

"True, the nature shows do put the dead mice on the table, but they take away from the hunting and stalking（围猎） I really like to do." 

"I'll put it on my calendar as something to do next week. Although, I've got to say, I would feel a little self-conscious wearing glasses out in public. What would the other eagles say?" 

"Honey, what other eagles think doesn't matter at all. It's more important that your eyesight be sharp and in focus. Anyway, these days they can fit you with contact lens that you hardly notice are even there." 

Ellen sighed. Maybe it was time for her to get her eyes checked. Could she really afford to keep bringing back lawn chairs for her hungry children? 

So the next day she flew over to the eagle optometrist（验光师） to have her eyes checked. The optometrist sat her down in a comfortable chair and asked her to identify the small animals on the tiny chart two miles away. "Mouse, chipmunk（花栗鼠）, gopher（囊地鼠）, squirrel, rabbit," she said, trying to sound confident. "It was difficult telling the difference between a mouse and a chipmunk. The shapes of these two animals were so similar." 

"Okay, you did well on that line of animals," said the optometrist. "Now see if you can read the animals on the line below it." 

Ellen concentrated all her mental powers on trying to see what the animals were on the next line. She could barely make out what the small animals were, so she made her best guess, "Hippo, elephant, giraffe, and rhinoceros（犀牛）," she said in a voice that lacked confidence. 

"I'm sorry, but you missed a few animals on that line. Your eyesight is far below the normal 2000/2000 eyesight of regular eagles. I'm going to recommend you get glasses or contact lens." 

"Can you tell me more about the contact lens?" inquired Ellen. 

"These days they have contact lens that are far more comfortable and far less bother than they were in the past," the optometrist explained. "And we happen to have a sale on them this week." 

"For three dead mice you can walk away with a pair of contact lens you can be proud of." 

"Three dead mice?" declared Ellen in a surprised voice. "I thought you could buy a decent pair of contact lens for two dead mice." 

"Well, it is true you could buy contact lens at other stores for two dead mice," replied the optometrist, "but they are inferior quality（低质量） contact lens. If you bought the cheaper contact lens, you might not be able to read the numbers on a license plate that was two miles away." 

Ellen shuddered at the thought. Not being able to read the numbers on a license plate two miles away was a sure sign that an eagle's eyesight was fading. 

"I'll take the three dead mice contact lens," she said quickly. As she flew out of the store she said to herself, "So it costs me an extra dead mouse. What's an extra dead mouse when you need to buy something to help your eyesight?" 

Her husband Ed leaped out of the lawn chair when she landed on the nest. "Honey, you're back so soon. Did you get a new pair of glasses or contacts?" 

"Sure did," Ellen replied with a renewed confidence in her voice. She hopped over to the back of the nest and casually nudged the lawn chair over the edge of the nest. 

"No more lawn chairs in this nest," she announced smugly（自鸣得意地）. "Only dead mice, rabbits, and fish are going to show up here in the future." 

"Honey, I was just getting used to the lawn chair when you nudged it over the side of the nest. Do you think you could find me another lawn chair sometime?" 

"No more lawn chairs in this nest, ever," said Ellen. "Okay, Ed, it's time we flew off to find something for the kids to eat for dinner. There's no use in just sitting around in lawn chairs all day."