11.The word "unrestricted"in line 4is closest in meaning to

(A)unsatisfactory

(B)difficult

(C)considerable

(D)unlimited

12.The word "snap"in line 9could best be replaced by which of the following?

(A)freeze

(B)click

(C)loosen

(D)break

13.What is the benefit of using two-stranded barbed wire?

(A)Improved rust-resistance

(B)Increased strength

(C)More rapid attachment of barbs

(D)Easier installation.

14.According to the author,the steel wires used to make barbed wire are specially processed to

(A)protect them against rust

(B)make them more flexible

(C)prevent contraction in cold weather

(D)straighten them.

15.The word "fed"in line 20is closest in meaning to

(A)put

(B)eaten

(C)bitten

(D)nourished

16.The knives referred to in line 21are used to

(A)separate double-stranded wire

(B)prevent the reel from advancing too rapidly

(C)twist the wire

(D)cut the wire that becomes barbs

17.What is the author's purpose in the third paragraph?

(A)To explain the importance of the wire.

(B)To outline the difficulty of making the wire

(C)To describe how the wire is made

(D)To suggest several different uses of the wire.

18.According to the passage,concertina wire is used for

(A)livestock management

(B)international communications

(C)prison enclosures

(D)military purposes.

19.Which of the following most closely resembles the fencing described in the passage?

(A)（图）

(B)（图）

(C)（图）

(D)（图）