题干

平面镜、凹面镜、凸面镜、凸透镜和凹透镜是五种常见的光学器件,其中利用光的反射定律的是____ ;利用光的折射定律的是____ ;能会聚阳光的是____ .

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平面镜、凹面镜、凸面镜,凸透镜、凹透镜,凹面镜、凸透镜

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    I'm part of the Roots & Shoots program founded by Dr. Jane Goodall. The program is intended to make and promote positive changes in the world. As Dr. Goodall says, “What you do makes a difference, and you have to decide what kind of difference you want to make.”

    In Bulgaria, where I live, homeless dogs are everywhere. Many people here turn a blind eye to them. But I cannot ignore the life of a street dog whenever I see one wandering in the street, looking for something to eat. That's why I'm no longer a food waster. When I see wasted food, I always think of a hungry dog climbing to garbage bins, searching for food that people have thrown there. When eating in a restaurant, I'm not afraid to take leftover food to feed stray cats or dogs.

    A week ago, I saw a homeless dog around the garbage bins. Immediately I knelt down, spoke to her softly and ran my hands over her. I could see that she had had puppies. I couldn't imagine how she could have been able to care for them. Hours earlier, I'd bagged up a plate of leftover fish. As I unwrapped it, she wagged her tail and sniffed at it. She ate all the fish in no time.

    It's sad, isn't it? I can't understand why many of us waste so much and think little of it. These homeless animals have taught me that food is precious. Even when I don't have leftovers with me, I'll take the time to get something from the grocery store to feed them.

    I know my power is small, so I hope that next time you see wasted food, do turn it into worthy food. You have the power to save a life!