单项选择题
A．A new type of fencing is introduced. B．Cattle ranching and farming in the United States. C．Barbed wire is better than singlestranded wire. D．How the wires were made in industry.
A．prevent the reel from advancing to rapidly B．twist the wire C．separate doublestranded wire D．cut the wire that becomes barbs
A．to suggest several different use of the wire B．to explain the importance of wire C．to describe how the wire is made D．to outline the difficulty of making the wire