题目内容：

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Oink! The Year of the Pig is coming. Many people believe that pigs are naturally fat, lazy and dirty. But are any of those things true?

Pigs are fat. They eat a lot. But they are useful to us. We get more than just pork from pigs. We can use their skin to make shoes. We can use their hair to make brushes. Pigs also provide us with materials for medicine.

People sometimes say: "You are as stupid as a pig.” But pigs are not stupid. In fact, pigs are one of the 10 smartest animals. They have a good memory and can tell different shapes apart. Many experts think pigs are easier to train than dogs or cats. In France, people teach pigs to find truffles which are a kind of plant with special smell. With their good sense of smell, pigs can find truffles even faster than dogs.

When you see pigs, they usually in dirty water or mud. That's because pigs have no sweat glands （汗腺）. On hot days, they have to cool themselves in water or mud. This keeps insects off of them as well. Mud can also protect their skin from sunburns.

The wrong opinions about pigs often make us dislike the animal. For example, if someone eats a lot, we say that they have "pigged out". If someone's room is very messy, we might say his or her room looks like a place where pigs live.

But people in ancient China really liked pigs. People thought the pig's big head was a symbol of good luck. If someone had a round and chubby（胖乎乎的）face, he or she was thought to be blessed（有福气的）.People also believed the animal stood for wealth. Piggy banks, a symbol of this. Most children have a piggy bank that they can use to save money.

1.What does the author think of pigs?

The author thinks that they are __________________________________________.

2.Why can a pig find the truffles quickly in France?

Because it has _______________________________________________________.

3.What does the fourth paragraph mainly tells us?

It mainly tells us the reason why __________________________________________.

4.According to the article, what was the symbol of good luck do ancient Chinese think?

______________________ was a symbol of good luck.

5.What does the underlined word "this" in the last paragraph refer to?

It refers to _________________________________________________________.