Bees seem to fly aimlessly as they search for the sugary liquid called nectar(花蜜). But their flight plans actually do have a pattern. Flowers act as the insects’ air-traffic controllers. And new research shows bees prefer flowers that aren’t too flashy.

Flowers give bees clues(线索) about how much food a plant has to offer. Those clues can be in the petals’(花瓣的) color, how much they shimmer(闪烁) or even in their electrical charge(电荷). All of these characteristics send signals to the bees telling them whether to land or not. Colors have a great influence on bees’ choosing flowers. The insects keep track of the color of flowers that are especially rich in nectar. They then visit more flowers of that color.

A flower’s color, however, isn’t a reliable guide to a good lunch. That’s because the color can change depending on the angle at which sunlight hits its petals. A yellow flower, for example, may look somewhat blue from one angle and red from another. Scientists call this kind of color change “iridescence”. Beverley Glover studies plants at the University of Cambridge in England. Glover and her colleagues showed even when petals look shimmery, bees can still tell which flowers likely hold food. They started to think the strength of a flower’s iridescence might be related to how bees find the petals. They tested their assumption in the lab.

They trained triple groups of bees to find purple flowers with more nectar. The first group of bees passed the test, ignoring flowers that weren’t perfectly purple. The second group got a little confused when purple flowers were perfectly iridescent. The third group of bees had no problem finding the right flowers when the petals had only a little bit of iridescent. That means imperfect iridescence is best for bees. The team shared its new findings in the Current Biology.

12. What plays a main part when a bee chooses flowers?

A. The color of the flowers.

B. The style of the flowers.

C. How much the flowers shimmer.

D. The electrical charge of the flowers.

13. What is “iridescence” that the scientists call?  

A. The flower changes its color when bees come to its petals.

B. The flower color changes itself when sunlight hits its petals.             

C. The flower color changes constantly when looked at under the sun.

D. The sunlit flower color is different when looked at from different angles.

14. The underlined word “triple” can be replaced by ____.

A. many         B. several        C. three          D. different

15. The research result of Glover and her colleagues is that ____.

A. iridescence attracts bees more

B. flowers make use of iridescence

C. bees prefer imperfect iridescence

D. rich colors instruct the fight of bees

第二节 （共5小题；每小题2分，满分10分）

根据短文内容，从短文后的选项中选出能填入空白处的****选项。选项中有两项为多余选项。

Free choir music for primary schools

Music is a subject most primary school children like and singing in a choir is an enjoyable way to perform and learn. There are many ways to achieve school choirs.

Online

Many musicians upload their works online. These scores (配乐) are mainly offered for sale but there are a great number of free scores available. Many of them are for choirs at grades 1 to 3 and 4 to 6. You can listen to the scores before downloading them.   16  

Other schools

A primary school usually belongs to a family of schools, consisting of other nearby primary schools and the high school.   17   Other primary schools in your family of schools may be able to lend, or give you choir music. Find out which of your colleagues is the person and explain your request. Your colleague should be able to help you.

Music advisory team

Many education authorities have education support teams of advisers, advisory teachers and subject specialists.

  18   If your education authority has a music support service, they may be able to supply you with free choir music for your school. Ask your music subject leader in school to find out about your music advisory team’s support for primary school choirs, especially with regard to providing free scores.

  19   

As well as general libraries, many cities also have specialized music libraries, which are likely to have collections of sheet music of many different kinds. Ring your nearest music library, in the first instance, to find out what they have, then go along and see for yourself if it seems promising.   20   Librarians are usually very helpful in helping users track down exactly what they are looking for.

A. Don’t be feared by rows and rows of tightly packed shelves of scores.

B. Friends

C. This can help you make sure whether they are suitable.

D. Their job is to promote learning in specific subjects.

E. But they are not familiar with choirs in fact.

F. Library

G. Families of schools sometimes share some resources.