We sometimes call the lion “the king of the jungle (丛林)” because it is stronger and more dangerous than other animals. It can run faster than many animals and it can hunt (捕猎) the best. It is the highest animal in the   21  food chain (食物链).[
In the sea, the shark is one of the animals at the  22  of the food chain. It can swim faster than most other sea animals, and it can use its big teeth to eat them.
What is at the top of the world’s food chain?  23  are! We are not the biggest or fastest, but we are the   24  We could not run faster than cheetahs (猎豹),  so we  25  cars and now we can move the fastest. We could not  26   better than lions, so we invented guns (枪). Now we can hunt the best.
People’s inventions are clever, but they can be dangerous, too. For example, people invented  27 , and now they make the air and rivers dirty. This can make   28  changes. Dirty rivers kill fish.  Then bears cannot eat the fish and the bears die. If we kill one part of the food chain,   29   also die. Remember that we are a part of the food chain, so we are in danger too! If we protect animals, we are protecting   30  ! We should and we could do something for the world!

A．land B．sea C．mountain D．desert

A．front B．end C．top D．beginning

A．People B．Lions C．Sharks D．Cheetahs

A．strongest B．cleverest C．most special D．most important

A．used B．had C．made D．invented

A．fight B．escape C．kill D．catch

A．hotels B．schools C．factories D．hospitals

A．great B．terrible C．wonderful D．complete

A．one part B．another part C．other parts D．the other parts

A．ourself B．yourselves C．themselves D．ourselves