阅读理解。 To wash yourself, you take a bath (洗澡) or a shower. Animals need to keep clean, too. How do animals clean themselves? Cats lick (舔) themselves to keep their fur clean. Have you ever watched a pet cat clean itself? Elephants take baths much as you do. But instead of jumping into the tub (浴缸), they walk into a river or lake. Pigs also like to roll around in water. This keeps them clean and cool. If there is no clean water, they will roll in mud (泥) on a hot day. They do this to cool off. Pigs do not really like mud. They are happier in a nice, clean pond (水池). Bats have a funny way to keep clean. They lick their thumbs to clean their ears! Guess how polar bears clean themselves. They use snow, of course! Some animals take baths in dust instead of water! The wombat (鼻袋熊) is an Australian animal with lots of fur. To get clean, it lies down. Then it covers itself with sand! Birds clean themselves in many ways. Sometimes they wash in water. That's why some people put birdbaths in their yard. At other times birds take dust baths, just like wombats. Birds also use their beaks (喙) to keep their feathers clean. They use their beaks the way you use a comb. Sometimes a bird has itchy bugs (发痒的虫子) in its feathers. Birds may use ants to help them clean off the bugs. A bird will lie down on an ant nest. Then the ants will crawl on the bird. The ants make a kind of bug spray (喷雾) on the feathers;. Then the itchy bugs die! Birds take baths in something else besides dust and ants! Some birds take 'smoke baths' They sit on chimneys. They wave their wings in the smoke! 1. This passage mainly tells us _____. [     ] A. why some people put birdbaths in their yard B. why birds allow ants to crawl on their body C. how animals cool off on hot days D. how some animals keep clean 2. What is a pig's favorite way to get clean? [     ] A. Licking itself. B. Lying down on ants. C. Rolling in nice, thick mud. D. Taking a bath in clean water. 3. Which of the following animals use dust to clean themselves? [     ] A. Cats. B. Bats. C. Wombats. D. Ants.