用下列所给单词的适当形式填空.something,not,tree,simply,spend,you,why,that,

用下列所给单词的适当形式填空.
something,not,tree,simply,spend,you,why,that,they,if,little,go,in,on,protect
The Earth needs a helping hand
The Earth is getting warmer because of the activities of people.We cut down and burn （1） and send gases into the air with our cars and factories.Can we do anything about it?Sure.We may （2） be leaders or scientists but we can play our part in （3） the planet.Here are two ideas.
Bike,don't ride to school
Do you （4） to school by bus or by bike?If you bike,you are doing （5） for the Earth.Buses,cars,trains and planes produce a lot of carbon dioxide (二氧化碳).If you live near to your school,(6) not bike there on warm spring mornings?Or,you can （7） walk to school to save energy.
Wash the green way
Do you help your mom and dad wash clothes?Then wash them （8）an energy-saving way.A recent study by Cambridge University found （9） 60 percent of the energy used on a piece of clothing is （10） in washing and drying it.Over it a lifetime,a T-shirt can send up to 4 kilograms of carbon dioxide into the air.
（11） you wash your own clothes,wash them in cold or warm water to save energy,but not hot water.Wash your clothes when （12） fill up the machine.Use the most energy-saving machine you can find.Some new ones use as （13）as one-fourth of the energy of older machines.When they're clean,dry (14) clothes the natural way,by hanging them (15) a line rather than putting them in a dryer.In all,you can cut the carbon dioxide used in washing by 90 percent.