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A
There are about 1,200 species of bats in the world, Swartz says. Some eat fruit. Others eat insects or honey. And just a few drink blood.
Some bats use their eyes to see where things are. Others collect information about their surroundings by bouncing sound off objects and listening to the echoes (回声).
But what all bats he in common (other than being the only flying mammals in existence) are flexible (灵活的) wings that enable them to change directions quickly. If you’ve ever seen bats flying with a rush through the air in the early evening, you probably noticed how suddenly they could change directions.
Scientists he long assumed (设想) that bats fly the same way as birds and insects do—with firm, airplane-like wings that connect to the shoulder. The problem with that assumption, however, is that bats aren’t birds or insects. As mammals, they he more in common with people, horses and dogs than with other flying creatures.
For example, birds he bones which are empty inside, and insects he no bones at all. But most mammals he solid and hey bones, which would make flying tough.
To solve this problem, bats he evolved strong and hey bones near their shoulders, where they need more support. They’ve also sed some weight by developing lighter and weaker bones near the tips of their wings. The result is light but strong and very flexible wings.
1. What can we know about bats from the passage?
A. All bats can hear sounds with their ears.
B. Bats are the same as birds in every direction.
C. Bats he nothing in common with people.
D. All bats can fly well because of their flexible wings.
2. It can be inferred that ＿＿＿ .
A. some bats may be dangerous to people
B. the scientists’ assumption is proved to be right
C. environment helps bats develop the ability of flying
D. bats collect information only by listening to echoes
3. What can be the best title of the passage?
A. BatsB. Bats’ Food
C. How Bats FlyD. Flexible Wings
B
In Western Europe homelessness has quietly been climbing to levels not seen since the end of World War II. According to the European Federation of National Organizations Working with the Homeless (FEANTSA), at least 3 million Western Europeans are homeless this winter—and between one-fifth and one-third of them are members of homeless families. Think homelessness is an American problem? Think again. As a percentage of population, it’s as bad in Europe as it is in the US, where there are an estimation (估计) of 2 million homeless people.
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