New research shows that sheep are clever

People often make jokes about how dull sheep are，but new research shows they may be cleverer than we think．Researchers at the University of Cambridge discovered that Welsh mountain sheep have brainpower that equals rodents （啮齿动物）．Tests found that the sheep can map the area they live in，and some may even be able to plan ahead．

Young fish prefer noisy neighbors

A new study has shown that young fish like to live on reefs with noisy neighbors!Researchers from the universities of Auckland and Bristol found that young fish looking for a home choose areas where other noisy fish live．The scientists produced all kinds of sounds which had been recorded in different natural environments．The young fish seemed to prefer the sounds of natural reefs，complete with noisy animals!The scientists compared the choice to a music fan wandering around at a music festival，choosing to set up a tent closest to the music they like best!

Butterflies are disappearing

A new study has shown that 17species of butterflies found in Europe have dropped by 70% in the last 20years．The information collected from 3，000sites across 15countries shows it may be caused by the loss of grasslands covered with flowers．You can encourage butterflies to come into your garden by planting flowers．

21．According to the first paragraph，we may infer that sheep___．

A．are less clever than rodents

B．can find their home

C．can read maps

D．are good planners

22．When young fish are looking for a home，they like to___．

A．live in a noisy environment

B．live in areas close to their parents

C．choose the reefs which are quiet

D．choose otherkinds of fish as neighbors

23．Which seems to have to do with the number of butterflies？___

A．The species of grass in grasslands．

B．The species of trees in grasslands．

C．The number of flo