Forest fires burn thousands of acres of land each year.They destroy animal and human homes，killing many creatures in their path. （1）

A

A

They make forests healthier by clearing out deadwood，making room for new trees.The heat of a fire is needed by some seeds before they can begin to grow.But，good or bad，forest fires need to be controlled.
   （2）

D

D

Firefighters rely on teamwork.This group of firefighters，known as a hand crew，will work together with a bulldozer（推土機(jī)）and a helicopter.The crew hike into the woods to cut a fire line.A fire line is a path through the forest stripped of all plants.Soil doesn't burn，so the fire won't cross this line if the line is wide enough.
   （3）

C

C

Using chain saws，the first two crew members cut the big wood out of the path.Next come two swampers，who clear away the wood.The next firefighters in line break up the ground and hack at the remaining plants.Last come firefighters with shovels and other hand tools.（4）

G

G

   To make sure the fire won't jump the line，a bulldozer follows the hand crew.In one pass，the bulldozer triples the width of the fire line.The hand crew follow the bulldozer to remove any plants left behind.
   （5）

F

F

A huge rubber bucket is carried beneath the helicopter.With the flick of a switch，the pilot releases the bottom of the bucket，and water pours to the ground.

A.But some forest fires also do good.
B.Forest fires do great harm to nature.
C.The hand crew work in a long line.
D.Let's see what it means to be a forest firefighter.
E.The work of firefighters is hard as well as dangerous.
F.If the fire threatens to jump the line，the crew call in the helicopter.
G.As each firefighter takes a swing at the ground，the fire line gets better.