2022-2023年英語週報九年級第2期答案彙總
Do you want something different for dinner? Try some space food. Many scientists are living for months aboard the International Space Station high above the earth. It's too expensive to carry food to feed people living in space. Therefore, people in space will need to grow food for themselves. But how can they grow food without soil and sunlight?
Today, we already have hydroponic vegetables. The science of hydroponics is not new. Many writers believe that the Hanging Gardens of Babylon were actually a large hydroponic system. This system could have used fresh water that was rich in oxygen and minerals for the plants. Hydroponic systems need light. In addition to sunlight, hydroponic farms can use artificial lights. Instead of soil, hydroponic farms use mixtures of chemicals to feed the plants. And in addition to a natural climate, most hydroponic farms often use greenhouses. One advantage of hydroponics is that diseases and insects that travel through the soil are avoided. Another advantage is there are no weeds to pull out.
Farmers know how to grow a few kinds of hydroponic vegetables, such as lettuces, tomatoes, and cucumbers. But in space, people will need to eat more than salad. So scientists are learning how to grow hydroponic rice, beans and potatoes. As they do these experiments, they are analyzing their results and examining how to apply these results to a real life situation providing tasty meals for space travelers.