①混合物：水玻璃、水银、水煤气

②电解质：明矾、冰醋酸、石膏

③酸性氧化物：CO₂、Al₂O₃、SO₃

④同位素：¹H、²H₂、³H

⑤同素异形体：C₆₀、金刚石、石墨

⑥干冰、液氯都是非电解质．

阅读短文，用方框内所给单词的正确形式填空，使短文意思通顺、完整。请将答案写在短文后相应题号的横线上。注意：①每个词只能用一次。②每空限填一词，有些词需要做相应的变化。③其中有两个多余选项。

  In many European countries it is normal to have a long break in the middle of the day when all members of the family return to their houses to eat together. This is not very ____ in Britain because normally it is a long way from the place of work or school to the home. The ____ people often have a big breakfast before they go to work and the meal at midday is not____ _with the members of the family but with workmates or schoolmates. Lunch is normally____ between 12:30 pm and 1:30 pm. Most people finish work at five thirty. It often take at _____ an hour to get home from the school or workplace so people eat their meal ____ "dinner" between 6:30 pm and 9 pm.
On Sundays people don’t have to work so they take the ____ to eat together with their family. Sunday lunch is ____ the best meal of the week and many of the meals which are considered real British food are eaten for Sunday lunch, such as roast beef and pudding.
____ everyone in Britain understands that "breakfast" is the first meal of the day, there is a lot of confusion(混乱) about the words for other meals such as "dinner, lunch, tea, high tea, elevenses, brunch, supper". And if you ask a British person what these words ____ , most of them will give you a different answer according to what part of the country they are from.

    Now satellites(卫星)are helping to forecast the weather. They are in space and they can reach any part of the world. The satellites take pictures of the atmosphere(大气), because this is where the weather forms(形成). They send these pictures to the weather station. So meteorologists(气象专家)can see the weather of any part of the world. From the pictures, the scientists can often say how the weather will change.
    Today, nearly five hundred weather stations in sixty countries receive satellite pictures. When they receive new pictures, the meteorologists compare(比较)them with earlier ones. Perhaps they may find that the clouds have changed during the last few hours .This may mean the weather on the ground may soon change, too. In their next weather forecast, the meteorologists can say this.
    So the weather satellites are a great help to the meteorologists. Before satellites were invented, the scientists could forecast the weather for about 24 or 48 hours. Now they can make good forecasts for 3 or 5 days. Soon, perhaps , they may forecast the weather for a week or more ahead(提前).