Do you know why different animals or pests（害虫）have their special colours？Colours in them seem to be used mainly to protect themselves．
Some birds like eating locusts（蝗虫），but birds cannot easily catch them．Why? It is because locusts change their colours together with the change of the colours of crops．Ⅵmen crops are green，locusts look green．But as the harvest time comes，locusts change to the same brown colour as crops have．Some other pests with different colours from plants are easily found and eaten by others．So they have to hide themselves for lives and appear only at night．
If you study the animal life，you’ll find the main use of culturing is protecting themselves．Bears，lions and other animals move quietly through forests．They cannot be seen by hunters．This is because they have the colours much like the tree．
Have you ever noticed an even more strange act? kind of fish in the sea can send out a kind of very black liquid when it faces danger．While the liquid spread over，the enemies cannot find it．And it immediately swims away．So it has rived up to now though it isn’t strong at all．
1．From the passage we learn that locusts ________．
A．are small animals B．are easily found by birds
C．change their colours to protect themselves D．are dangerous to their enemies
2．How can pests with different colours from plants keep out of danger?
A．They run away quickly．
B．They hide themselves in the day and appear at night．
C．They colours much like their enemies．
D．They have to move quietly．
3．Bears and lions can keep safe because they ________．
A．live in forests B．move quickly
C．like brown and grey colours D．have the colours much like the trees
4．The kind of fish live up to now because ________．
A．the liquid it sends out help it escape from its enemies
B．it is very big and strong
C．the liquid it sends out can kill its enemies
D．it swims faster than any other fish
5．Which is the best title for this passage?
A．The Main Use of Colours for Animals and Pests
B．Colours of Different Animals and Pests
C．The Change of Colours for Animals and Pests
D．Some Animals and Pests