_________ take the train instead of the bus? It's faster.
A.How about
B.Let's
C.Why don't
D.Why not

We are now facing the possible________ of several rare species.
A.danger
B.variety
C.existence
D.disappearance

Would you like lunch with us?' `Yes, I'd love to.'
A.have
B.to have
C.having
D.had

A.eliminate
B.elephant
C.endanger
D.erosion

A.pollute
B.species
C.accept
D.receipt

A.environment
B.hydroelectric
C.circulation
D.wild

A.club
B.lamb
C.doubt
D.bomber

A.disappearance
B.circulation
C.conservation
D.environment

A.nature
B.power
C.damage
D.defence

A.injured
B.valuable
C.forest
D.protect