单项选择题
A．Easier installation. B．Improved rust-resistance. C．Increased strength. D．More rapid attachment of barbs.
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