A、How to handle spiders. B、Spiders in the United States. C、People’s fear of spiders. D、A special kind of spider. B选项综合性强，本题可能考查短

You should not fear spiders because of their poison. Of all the spiders in North America, only one kind is very dangerous and most would not bite even if they were handled. They much prefer to run away or to drop to the ground on a thread of silk. Even so, when a spider runs directly toward a person, it gives the impression that it is about to attack. Actually, it cannot see the person in its way. The spider is too shortsighted to see things at a distance. It only wants to go where it won’t be disturbed. In the United States one kind of spider is responsible for the frightening reputation of the rest. It is the Black Widow, so called because the female, which is larger than the male, often eats her husband after making love. The Black Widow is found in all states but is most common in the south and the west. She constructs a loose, irregular web under a pile of ruins or near the foundations of buildings where she is seldom disturbed. She is not an attacking spider and many people have proven this by letting her crawl over their hands. When she bites, it is usually in self-defense. In spite of the stories you may have heard, it is rare for a person to be bitten by a Black Widow and even more unusual for the bite to prove fatal. But remember that her poison is powerful and even though she is shy, she should be respected.
Questions 30 to 32 are based on the passage you have just heard.
30. What is this passage mainly about?
31. What do we learn about spiders from the passage?
32. Why is the spider you just heard about called Black Widow?