B．tries hard to be fun and friendly

　　C．doesn't get along well with the writer

　　D．is busy with her study all the time

　　解析：　推理判断题。从第三段的Our other roommate is kind of mean to us，so there is always awkward tension in our room可知C项正确。

　　答案：　C

　　4．The passage was written mainly to________.

　　A．show the writer's independence

　　B．introduce the writer's college life

　　C．show how to apply for the school

　　D．persuade people to study abroad

　　解析：　作者意图题。作者主要在文中介绍了自己全新的大学生活。

　　答案：　B

　　To the untrained eye it might seem like just a bit of a monkey trick.But when Milly the mandrill (山魈，西非洲产的大狒狒) covers her face with her hand she is actually sending a serious message to her fellows："Leave me alone！"

　　Experts believe the 15­year­old mandrill invented the gesture to warn other monkeys at Colchester Zoo to give her some space.And，surprisingly，the signal has been picked by other members of the group，who use it when they too require solitude.

　　Biologist Mark Laidre believes the behavior is evidence of social culture among the mandrills.Importantly，the sign language is unlikely to have been influenced by human activities because mandrills do not copy humans.Mr Laidre expects further research will uncover other monkeys using cultural gestures-the ability to communicate with the hands in a meaningful way."By covering their eyes with their hands，individuals possibly conveyed to others that they wanted to be left alone and this message may have been respected as a 'do not disturb' sign，" said Mr Laidre.

While the hand is in place，other monkeys are not likely to approach or touch the monkey.Those who rank lower in the social order also use the technique to avoid attacks from more powerful group members.As the discovery appears to be unique to Colchester Zoo，it suggests it is a local phenomenon that arose naturally in the community of 25 mandrills.