People must conserve more energy.
More energy must be conserved.
We must use more natural products.
More natural products must be used (by us).
Artists can reuse junk into art.
Junk can be reused by artists into art.
Designers can use natural and renewable materials to make clothes.
Natural and renewable materials can be used by designers ...
People must design more energy-efficient cars.
More energy-efficient cars must be designed.
We can recycle old computers into smartphones.
Old computers can be recucled into smartphones.
People should reuse more green shopping bags.
More green shopping bags can be reused by people.
We must reduce plastic waste in the future.
Plastic waste must be reduced in the future.
We should close the windows to conserve energy.
The windows should be closed ...
We can reuse glass bottles to make art.
Glass bottles can be reused to make art.
People can melt and reuse glass again to make windows.
Glass can be melted and reused by people .....
People should recycle more plastic stuff.
More plastic stuff should be recycled by people.
Artists can find old stuff to make art.
Old stuff can be found by artists to ...
We can grow renewable materials like cotton on farms.
Renewable materials like cotton can be grown ...
We should not throw away chemicals outside.
Chemicals should not be thrown away outside.
People should use natural materials more often.
Natural materials should be used ...
We can use tools to paint the table.
Tools can be used to paint the new table.
People can build houses on the moon.
House can be built on the moon.
People should not throw away garbage in the river.
Garbage should not be thrown away in the river.
We can recycle paper into new bags.
Paper can be recycled into new bags.
Everyone should recycle cans.
Cans should be recycled (by everyone).
Carmakers can design flying cars in the future.
Flying cars can be designed by carmakers in the future.
Engineers should build more energy-efficient fridges.
More energy-efficient fridges should be built by engineers.
A Scottish artist could make sculptures from magazines.
Sculptures could be made by a Scottish artist ...
We can recycle some man-made materials like plastic.
Some man-made materials like plastic can be recycled.