【推荐1】There are some places in the world where great cities once stood. There were gardens, trees and grass. But now these cities have gone and the places are like deserts. Scientists began to study this land to find out what happened. Many of them believed the land died when the trees were cut down.

Trees help other plants grow and help hold the soil in place. They keep the soil from blowing away. The leaves of trees on the ground keep rainwater from running off. Trees near farms protect growing plants rainwater from running off. Trees near farms protect growing plants from strong winds.

Once there were hundreds of farms in the Southwestern United States. Then the farms turned into fields of dry dust (尘土). Trees might have saved these farms. But few trees grow in the dry Southwest now.

Now we try to save trees. In many places, when a tree is cut down, a new tree is planted in its place. We do not want the land to die.

【推荐1】Have you ever seen one of the many videos of an elephant catching a paintbrush, putting it in paint, and producing a painting similar to something a 5-year-old could create? While watching an elephant paint is an amazing sight, we can’t help but wonder whether the training methods and results reflect animal cruelty.

A 2014 study on four captive (圈养的) Asian elephants at the Melbourne Zoo in Australia was carried out to identify stress-related behaviors around the activity of painting. While the researchers found that the elephants had a neutral (中立的) response to painting — not stressful, nor enriching- it seemed that when an elephant was not selected to paint, it displayed non-interactive behavior. This is seen as a possible signal of stress in the animals.

In addition, PETA, a famous animal rights group, has mentioned several American zoos that use harmful training methods to get elephants to paint, perform tricks, play instruments, and more. That is to say, some zoos that organize elephant painting use assaults to encourage the elephants. However, PETA argues that animal shelters should not force animals to do tricks at all.

Activist organizations warn that elephants can undergo extreme discomfort in the training process. Furthermore, many of the painting elephants are very young, at an age where they should still be with their mothers. It raises questions about whether there’s a chance they were caught for the express purpose of performing, or whether they could somehow be restored to a return to the wild.

It is difficult to support any kind of trained behavior that differs greatly from a wild animal’s natural tendencies. The role of a shelter is to allow an animal to live as close to its normal life as possible, perhaps with an eye to returning the animal to the wild; teaching them to paint does not seem to go with that target, particularly if it’s not a learned behavior that the animal would be willing to do independently.

【推荐2】It is easier to float in the ocean than it is to float in a swimming pool. Do you know why？

Ocean water is full of salt—and salt water can hold up more weight than fresh water. See for yourself！

You Will Need：

3 cups of warm water

·Measuring cup（量杯）

·Wide-mouthed jar

·Salt

·Spoon

·Raw（生的）potato

You Will Do：

1. Pour 1. 5 cups of warm water into the jar.

2. Add 1/3 cup of salt.

3. Stir（搅拌）until the salt is completely

4. Add another 1. 5 cups of water. Pour it slowly over the spoon into the jar so that the two liquids will not mix together.

5. Gently place the potato into the jar. Do not drop it.

What Will Happen:

The potato will sink—but only halfway!

Why?

Salt water is heavier than fresh water，so it will stay on the bottom. The fresh water will remain on top.

The potato is heavier than the fresh water, but it is lighter than the salt water. That is why the potato will sink halfway down.

【推荐3】A survey in the Philippines has shown the country uses a “shocking” amount of single-use plastic, including nearly 60 billion sachets (小袋) a year, a new report said Friday. The report, produced by the non-governmental organization GAIA, is part of an effort to collect data on plastic consumption as environmentalists push for government action to reduce plastic waste.

It contains shocking figures: every day, almost 48 million shopping bags are used throughout the Philippines, adding up to more than 17 billion a year.   And that figure does not include the smaller, thinner and often transparent plastic bags known as “labo” bags—around 16.5 billion of those are used per year across the country, the report says. The figures are based on 21 waste assessments conducted in 13 cities across the Philippines, with the national figures produced by extrapolating(推断) from local results.

More than half of non-recyclable plastic analyzed in the survey came from sachets—small plastic packets often lined with aluminium or containing other materials that make them non-recyclable.   Small portions of products ranging from coffee to shampoo are often sold in sachets in the Philippines, and are seen as an affordable solution for consumers.

But Grate said the popularity appeared to be more a result of what is available, with wealthier consumers simply buying multiple sachets. “If you go to the supermarkets, it’ s rare for you to be able to buy coffee in bigger containers; it’s all in sachets,” he said.

The survey is the first time an organization has tried to quantify(确定数量) sachet use, and the NGO hopes to pressure both the government and industry to take action on controlling single-use plastic. The report found that where local-level plastic bag bans have been put in place and strictly enforced, usage has dropped dramatically.

It urged the government to “institute a comprehensive national plastic bag ban that promotes reusable bags”. And it wants regulations on other single-use plastic products and rules requiring companies to redesign products and packaging to minimize plastic waste.