If you are asked the question "What colour is the sky?" I believe you will answer blue. But I am afraid you are{#blank#}1{#/blank#}. The sky has no color. When we see blue, we are looking {#blank#}2{#/blank#} the blue sunlight. The sunlight {#blank#}3{#/blank#} on the little bits of dust(灰尘) in the air.

    Is the sky full of {#blank#}4{#/blank#}? I am sure that you are asked this question, {#blank#}5{#/blank#}. We know that there is air all around the world. We could not live{#blank#}6{#/blank#} air. Planes could not {#blank#}7{#/blank#} if there is not any air. If we go far enough {#blank#}8{#/blank#} from the earth, then we will find there is no air. Perhaps we can answer some of our questions now.{#blank#}9{#/blank#} is the sky? The sky is space. It is all around the world. There is nothing but the sun, the moon and the stars {#blank#}10{#/blank#}space.

    It's very important to know something about traditional presents. In the West, people often take flowers when they {#blank#}1{#/blank#} others. Different flowers have different {#blank#}2{#/blank#}. For example, people often give red roses to {#blank#}3{#/blank#} who they love. In Greece, you must not give white flowers because white flowers are for the {#blank#}4{#/blank#}. When you go to a foreign country, it is always best to check what people {#blank#}5{#/blank#}do. If you remember this, you can avoid making a lot of mistakes.