15 minute test

Dinosaurs became _________ millions of years ago.

• extinction

• extinct

• decrease

• extinctive

chemical pollutants are discharged _____ the river everyday.

• on

• to

• into

• in

Oil, coal, and natural gas are _________ fuels made from decayed material from animals or plants.

• Solid

• resources

• Fossil

• energy

Many efforts have been made to protect the ____ nature.

• danger

• dangerous

• endanger

• endangered

_________is a great source of energy but very dangerous.

• nuclear energy

• solar energy

• water energy

• hydroelectricity

Many national parks have been established to protect endangered animals.

• decorated

• set up

• encourage

• make use of

Our well-trained staff are always courteous to customers.

• abundant

• patient

• polite

• rude

Solar energy is not only plentiful but also infinite.

• strong

• weak

• limited

• unlimited

If people stop destroying animal's natural habitat, more species will survive and produce ______.

• benefit

• landscape     

• ecology

• offspring

People are destroying the air by adding ______ to it.

• polluters

• pollution

• pollutants

• polluted