閱讀下面短文，根據(jù)語(yǔ)境、音標(biāo)或所給的單詞提示，在每個(gè)空格內(nèi)填入一個(gè)恰當(dāng)?shù)脑~，要求所填的詞意義準(zhǔn)確、形式正確，使短文意思完整、行文連貫。
The bicycle is one of the most important（1）

vehicles

vehicles

（vehicle） in the world.In every country people use bicycles for work，for sport of just for（2）

fun

fun

/f?n/.
Bicycle riding is good exercise.It（3）

helps

helps

（help） people become fit.Bicycle riding can make the riders' hearts and lungs strong.It is（4）

also

also

/'?：ls??/ good for the environment because bicycles do not cause pollution.
   Bicycles share the road with cars and trucks.Drivers do not always（5）

notice

notice

/n??t?s/ bicycles.（6）

So

So

bicycle riders must pay attention to the traffic around them and know traffic signals.They must know and obey the（7）

safety

safety

（safe） rules.They must wear helmets to protect their heads.When riding at night，they must wear light-colored clothes，and have lights in the front and reflectors on the back of their bicycles.A bicycle accident may be serious.In case（8）

of

of

an accident，bicycle riders should know how to give first aid.If（9）

an

an

injury is serious，they must call 120 for help.In a word，the（10）

best

best

（good） way to be safe is to be careful.