It may be concluded from this passage that___________.
A.only some cultures have signs, signals, and symbols
B.signs, signals, symbols, and gestures are forms of communication
C.symbols are very easy to define and interrupt
D.waving and handshaking are not related to culture

What does the passage mainly discuss?
A.The history of railroads in theUnited States
B.The majorUnited States industrial centers
C.Factors that affected industrialization in the United States
D.The role of agriculture in the nineteenth century

The word “ themselves” in the paragraph 2 refers to _______
A.sources
B.centers
C.railroads
D.places

There is growing concern about the way man has destroyed the environment.
A.ease
B.attraction
C.consideration
D.speculation

Men and women in the Peace Corps work with people in the developing countries to help them improving their living conditions.
A.work
B.developing
C.improving
D.living

Although not widely sold, that book is considered to be best book on the subject.
A.not
B.sold
C.best
D.the

I found my new contact lenses strangely at first, but I got used to them in the end.
A.my new
B.strangely
C.got used
D.in the end

________(41)
A.developed
B.brought
C.advanced
D.grew

________(42)
A.circumstances
B.occasions
C.incidents
D.situations

__________is the existence of a large number of different kinds of animals and plants which make a balanced environment..
A.extinction
B.biodiversity
C.habitat
D.conservation