The recent cold weather in the United States has had some unusual effects. In South Florida, temperatures dropped so low that iguanas(鬣蜥) began falling out of trees.

As temperatures began dropping in South Florida, the US National Weather Service began warning that iguanas might soon be falling from trees. It didn’t take long for the prediction to come true. Several people posted pictures of the fallen iguanas on social media. As one person wrote, “It’s true. It’s raining iguanas in South Florida.”

What happened? They became unconscious because of the severe cold. Iguanas are cold-blooded. That means they don’t make their own body heat like humans. Instead, they get their warmth from their environment—the sun, the air, and warm objects around them. When the temperature gets too cold, the iguanas’ bodies slow down and they fall into a kind of sleep. For iguanas in trees, that means they can lose their hold and fall to the ground. That’s what happened this last weekend, when South Florida had its coldest weather in over 10 years. In some places, it got down to 25º Fahrenheit(华摄氏度)(-4º Celsius).

If you don’t think it seems natural for iguanas to have this problem, you’re right. Green iguanas aren’t actually supposed to be in Florida at all. They are originally from warmer places in Central and South America. They were brought to Florida by accident. Some were carried on ships. Others came as pets and somehow got free. Green iguanas are considered an invasive(入侵的) species in Florida.

Even though the iguanas may look dead, they’re usually not. This weekend, experts warned people in Florida not to bring the iguanas inside to warm up. Once they recover, they’re not always friendly.

1.What does the underlined part “the prediction” refer to?

A Temperatures dropping.

B Iguanas falling from trees.

C Pictures of iguanas on social media.

D The cold weather in the USA.

解析：选B。B 词意指代题。根据第二段第一、二句可知“the prediction”指的是前一句美国国家气象局提出的警示“iguanas might soon be falling from trees”，故选B。

2.Why do some iguanas fall out of trees?

A They are cold-blooded animals.

B They get warmth from their environment.

C They fall asleep easily in cold weather.

D They become unconscious and lose their hold.

解析：选B。B细节理解题。根据第三段第一句的 “They became unconscious”以及 “they fall into a kind of sleep. For iguanas in trees, that means they can lose their hold and fall to the ground.”可知，鬣蜥失去了意识进而造成它们在树上待不稳，然后掉到了地上。故选B。

3.We may learn from the text that iguanas are _________.

A native in Florida

B friendly to people

C afraid of human beings

D easy to find in Central America

解析：选D。D 推理判断题。根据第四段的“They are originally from warmer places in Central and South America.”可知鬣蜥最初来自中美洲和南美洲较温暖的地方，由此说明在中美洲比较容易看到鬣蜥，故选D。

4.Which of the following can be the best title for the text?

A Extreme Weather in Florida

B Iguanas: An Unusual Animal Species

C Coldness Led to Iguanas Falling from Trees

D The report from the US National Weather Service

解析：选C。C 主旨大意题。本文主要介绍了佛罗里达极寒天气导致鬣蜥被冻僵从而从树上掉下来的相关情况，因此C项的“寒冷导致鬣蜥从树上掉下来”符合文意。故选C。