阅读理解

阅读下面短文，从每题所给的四个选项(A、B、C和D)中，选出最佳选项。

　　The most striking single fact about chimpanzees is the flexibility of their social life the lack of any rigid form of organization. It represents about as far a departure from the baboon(狒狒) type of organization as one can find among the higher primates(灵长类动物) and serves to emphasize the great variety of primate adaptations. Chimpanzees are more human than baboons or rather they jibe better with(与……相一致) the way we like to picture ourselves as free-wheeling individuals who tend to be unpredictable do not take readily to(喜欢) any form of regimentation(限制) and are frequently charming. (Charm is relatively rare among baboons.)

　　Two researchers have described what they found during more than eight months spent among chimpanzees in their natural habitat the forest:“We were quite surprised to observe that there is no single distinct social unit in chimpanzee society. Not only is there no ‘family’ or ‘harem’(妻妾) organization; neither is there a ‘troop’ keep permanently together. On the contrary individuals move about at will alone or in small groups best described as bands which sometimes form into large aggregations. They leave their associates if they want to and join up with new ones without conflicts.

　　The general practice is best described as “easy come easy go” although there are certain group-forming tendencies. As a rule chimpanzees move about in one of four types of band: adult males only; mothers and offspring(后裔) and occasionally a few other females; adults and adolescents of both sexes but no mothers with young and representatives of all categories mixed together. The composition of bands may change a number of times during the course of a day as individuals wander off and groups split or combine with other groups. On the other hand certain individuals prefer one another's company. One of the researchers observed that four males often roamed together over a four-month period and mothers often associated with their older offspring.

1．The passage is mainly about ________.

[　　]

A．the difference between chimpanzees and baboons

B．the charm of chimpanzees

C．the flexibility(灵活性) of chimpanzees' social life

D．the similarities with chimpanzees and human beings

2．According to the first paragraph baboons are ________.

[　　]

A．one kind of the higher primates

B．frequently very charming

C．more human than chimpanzees

D．like free-wheeling individuals who tend to be unpredictable

3．According to the author which of the following statements proves the great variety of primate adaptations?

[　　]

A．The flexibility of chimpanzees' social life.

B．That baboons are rarely charming.

C．That chimpanzees do not take readily to any form of regimentation.

D．That the organization of chimpanzees represents a far departure from that of the baboon type.

4．After more than eight months of observation the two researchers found out that ________.

[　　]

A．chimpanzees often form permanent families

B．individual chimpanzee never moves alone

C．there is often conflict when a chimpanzee leaves its associates and joins up with new ones

D．there is no single distinct social unit in chimpanzee society

5．Which of the following sentences is NOT a type of band in which chimpanzees move about?

[　　]

A．Adult females only.

B．Mothers and offspring and occasionally a few other females.

C．Adults and adolescents of both sexes but no mothers with young.

D．Representatives of all categories mixed together.