Most dog owners have probably been puzzled waiting for their dog to do its business. Instead of justfinding a soft area of grass to go number two, they make a whole ritual(仪式)out of it, spinning in a circlebefore finally squatting(蹲下). Luckily, the ultimate pet owners’ question may finally have been answered.
   A few theories have circulated about why dogs might circle before pooping, and most are similar tothe reasons they spin before lying down. Trampling around in a circle would flatten the grass around, which would keep tall blades(叶片) from trapping their waste. Another explanation could be that they’re scanning for snakes and predators before they become completely occupied.
But Czech researcher Hynek Burda didn’t quite buy into those theories. Dogs evolved from wolves, which didn’t need to worry much about tall grass. And if they were scanning their environment, keeping still to listen and sniff would be more effective than giving the area a quick once-over. Instead, Burda suggested that dogs spin to get a feel for the Earth’s magnetic pull.
The Earth has a magnetic field around it protecting it from radiation from space, and some animals seem to use it to get a sense of where its North and South poles are. For instance, it’s how birds know which way to migrate. In 2013, Burda published a study in the journal Frontiers in Zoology suggesting dogs have a strong internal compass, too. He and his team spent two years watching 70 dogs poop and peeand recording which way they faced and how strong the magnetic(磁的) field was.
As it turns out, when the magnetic field was calm, dogs preferred to poop facing either north or south. The pattern couldn’t explain why dogs like facing the Earth’s poles, but the researchers think it might help them remember where they marked their territory.
If they can remember which way they were facing, they might find it easier to find that spot again. So before you roll your eyes when your dog takes ages to do his business, remember that Fido might just be getting scientific about his potty spot.
24.What is the ritual for dogs when they do their business?
A.They poop twice daily. B.They circle before pooping.
C.They usually make their owner impatient. D.They just find a soft area to poop.
25.According to Burda, dogs__________.
A.look for snakes and predators before pooping
B.spin to flatten the grass
C.sniff around to scan the environment
D.circle to face a certain direction
26.The writer cites “birds” in order to show____________.
A.how magic they are B.dogs also can migrate
C.dogs have inner compass D.the differences between birds and dogs]
27.It might be concluded that dogs ____________.
A.have good reasons to take ages to do his business
B.are more scientific than human beings
C.are sensitive to radiation from space
D.often play tricks with their owners 这是一篇说明文。为什么狗在大便之前要花费很多时间转圈找地方？最新研究表明，狗和鸟类一样有一个体内“指南针”。转圈的目的是定位，对地球磁场感应使得狗可以对准北极或者南极上“二号”。
24. 选B。题眼在第一段。Do business, go number two 和poop都是指的同一回事。
25. 选D。新的研究结果表明狗转圈是为了找准方向。
26. 选C。提到鸟类是为了说明狗也有方向感。
27. 选A。对最后一句的解析。主人在狗长时间转圈的时候不要翻白眼（不耐烦），因为他们正在寻找“科学”的位置，也许为了下次能够更容易找到这个地方，也许是上一段提到的更好地标记地盘，总之，他们有理由这么做。这句话很幽默。