Bull sharks (牛鲨) have friends too, scientists have discovered. People usually think sharks live alone, but a new study suggests that bull sharks have friends they like to spend time with.

Scientists watched 184 sharks over six years. The sharks were fed together inside a protected area. Researchers could go deep down and watch them. The team recorded their actions, such as sharks leading and following each other and how close together the sharks swam.

They found that both male (雄性的) and female (雌性的) bull sharks like to play with females, but males form more social relationships. This might be because males are smaller than females, so having more friends protects them from larger sea animals.

The researchers said that like other animals, bull sharks might learn new skills, find food and stay safe from enemies by social connections.

“As humans, we build different kinds of social relationships. And these sharks are doing similar things,” said Natasha Marosi, who led the research. The scientists said understanding bull sharks’ actions can teach us more about how they live together and move around, which can help with shark protection.

1.1. What does the new study find about bull sharks?

A They live alone.

B They like humans.

C They have friends.

D They feed each other.

解析：选C。答案：C - 题型：细节理解题 - 解析：文章开篇点明新研究的发现 “bull sharks have friends too”，牛鲨也有朋友。 A 错误，人们普遍认为鲨鱼独居，这不是新研究发现；B、D 文中没有相关信息。

2.2. What might be the reason for male sharks to form more social relationships?

A They need protection.

B They want to be leaders.

C They need more areas.

D They want to meet females.

解析：选A。答案：A - 题型：细节理解题 - 解析：原文 “This might be because males are smaller than females, so having more friends protects them from larger sea animals.” 雄性体型更小，更多的同伴能够为它们提供保护。B、C、D 原文无依据。

3.3. What is the last paragraph mainly about?

A The meaning of the study.

B The cause of human action.

C The advantage of social life.

D The way of shark protection.

解析：选A。答案：A - 题型：段落主旨题 - 解析：最后一段引用研究者话语，说明牛鲨社交和人类相似，点明这项研究能够帮助我们了解牛鲨生活习性，助力鲨鱼保护，讲的是**这项研究的意义**。 B “人类行为的起因” 文中未提及；C “群居生活的好处” 是前文内容；D “鲨鱼保护的方式” 只是其中一个细节，不是整段主旨。