When  18thcentury  scientists first came across Australia’s platypus (鸭嘴兽)，they thought it was a trick.It is not surprising that the platypus made people confused.This funnylooking animal has feet and is a kind of warmblooded mammal(哺乳动物)．
While other mammals usually keep their blood at around 37 degrees，the platypus has a lower body temperature of 32 degrees.As to its appearance，the platypus’ mouth is not really like the duck’s; its mouth actually looks a bit softer.The platypus closes its eyes when swimming instead of watching its hunters.It uses its mouth to pick up outside information made by the creatures underwater.
Strangest of all，the platypus is a mammal that can lay eggs.And there is only one other kind of mammal that can lay eggs，the echidna(针鼹鼠) of Australia.Both the platypus and the echidna lay soft shelled eggs，and both feed their young with their own milk that comes out of their skin.These animals also walk in a way that is similar to crocodiles (鳄鱼)，with legs on the sides of their bodies rather than under them.
Though pretty in a special way，the platypus is actually one of the few mammals that are poisonous.A male platypus has knifelike bones on its back legs which have enough poison to kill a dog.
The platypus has the honor of being one of the oldest mammals in the world.Until the early 20thcentury，it was hunted for its fur，but it is now protected.Although the platypus is easily influenced by pollution，it is not under any immediate threat.
What can we learn about the platypus?

A．It has a lower body temperature than other mammals.

B．It only closes its eyes when underwater.

C．It’s the only poisonous mammal in the world.

D．It feeds its young on wild animal meat.

Which of the following is NOT used as a comparison in    the passage?

A．The crocodile.

B．The echidna.

C．The duck.

D．The dog.

The characteristics of the platypus that have been described in the passage include________．
a．the color of its skin
b．the way it gets information
c．its walking pose
d．its strange appearance

A．b－c－d

B．a－b－c

C．a－c－d

D．a－b－d

We can learn from the last paragraph that the platypus is________．

A．hunted for its meat

B．in danger of extinction

C．endangered because of air pollution

D．wellprotected now