The Chihuahuan Desert in West Texas is larger than any other desert in North America. There winters are cool and summers are very very hot. This area is also home to a mysterious phenomenon (神秘现象) called the Marfa Lights.

The Marfa Lights are bright lights that appear in the night sky all of a sudden and then fly to faraway places and disappear. They are about the size of basketballs and are often described as white, blue, yellow, red or other colors. The lights sometimes even get close to people’s houses. One woman who lived on a farm told the story of what she experienced one night. She was in bed and suddenly she saw the lights shining through her bedroom window. She watched them change color for a few minutes. Finally, they went away. Pilots who used to train in the desert in the 1940s also reported that they once saw these mysterious lights.

What causes this phenomenon? People have different opinions on this. A popular interpretation is the lights might have something to do with headlights from cars on the road nearby. Scientific research also suggests that some of the lights are caused by the refraction (折射) of light between layers (层) of air that have different temperatures. However, not all of them can be explained so easily.

Anyway, people will continue to study the lights to find out where they come from. No matter what these lights really are, they are as mysterious today as when they first appeared. But it is certain that the mystery behind them will ever be solved one day.

①One day, you open the fridge and find some moldy (发霉的) food. But before you throw it away, your mother stops you. She doesn’t want to waste food. She cuts off the moldy part and eats the rest. Is it safe to do this?

②Most kinds of mold (霉菌) are bad for us. It can grow on almost all kinds of food. Mold is usually green, white, black or grey. Mold makes food soft and changes its color. Moldy food tastes quite bad and it’s not safe to eat. So how do you deal with this situation?

③If you find mold in soft food, just throw it away. Soft food, such as bread, tomatoes or hot dogs, usually contains water. This allows mold to easily grow below its surface. Bacteria (细菌) can also grow along with it. It’s easy to remove mold from hard food. The mold can’t grow very deeply inside this kind of food. According to the BBC, you should cut about 2.5 cm around and below the mold to remove it. It’s OK to cut the moldy parts out of hard food and eat the rest. But if the food is completely covered with mold, you should still throw it away.

④But some kinds of mold have good influence. Some kinds of mold can be used to make food. For example, penicillium (青毒菌) can be used to make many different kinds of cheeses, such as blue cheese. These cheeses are safe to eat and they’re quite delicious as well.

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Most young boys don’t like growing flowers and watering them. But for 16-year-old Angus, working in the garden isn’t just a hobby—it has changed his life.

Angus has a special illness and his IQ is lower than an ordinary boy. Six months ago, he started learning how to grow flowers. Now, he spends hours in the garden growing flowers, watering and looking after them. “Before working in the garden, it was difficult for Angus to pay attention to class and sometimes he didn’t want to go to school,” said his mother Kim. “Now he can’t wait to go to school and he is happy every day. We can see Angus is able to work in a garden center in the future.”

Research shows that working in the garden improves mental and physics health （身心健康）. In the past, soldiers in Egypt treated their mental problems after war by working in the garden. Even now, some doctors advise people to work in the garden to treat their mental health problems. And doctors also advise young people like Angus to work in the garden.

The lives of hundreds of children in Britain with special needs, like Angus, have been changed by this special kind of education. When working in the garden, children have a chance to learn a lot of important skills, such as how to work with other people and how to take care of plants. Besides, the children become more confident after working in the garden.