Erosion, which washes (A) away valuable topsoil, can prevent (B) by (C) planting trees and grass. (D)
A.washes
B.can prevent
C.by
D.grass

It is estimated (A) that much of (B) a teenager's time is spending (C) chatting on the Internet.
A.is estimated
B.much of
C.spending
D.chatting

Tom: “Do you know where Barb is?” Mary: "Strange ______sound, she is in South Africa.”
A.may it
B.as it may
C.like it may
D.does it

Half the world's rain forests have already been ___________.
A.endangered
B.eroded
C.found
D.destroyed

Endangered animals should be bred in _______ areas.
A.conservative
B.conservable
C.conservation
D.conservance

Acid rain has caused severe _______ on the hillside.
A.erosion
B.pollution
C.destruction
D.floods

Can you please tell me some information_____to the job?
A.that indicates
B.that are relating
C.that relate
D.relating

A large hydroelectric __________was built on the River Danube.
A.power
B.dam
C.bank
D.wall

_________ 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