Throughout the 19th century and into the 20th, citizens of the United States maintained a bias against big cities. Most lived on farms and in small towns and believed cities to be centres of (1) , crime, poverty and moral (2) Their distrust was caused, (3) , by a national ideology that (4) farming the greatest occupation and rural living (5) to urban living. This attitude (6) even as the number of urban dwellers increased and cities became an essential (7) of the national landscape. Gradually, economic reality overcame ideology. Thousands (8) the precarious (不稳定的) life on the farm for more secure and better paying jobs in the city. But when these people (9) from the countryside, they carried their fears and suspicions with them. These new urbanities, already convinced that cities were (10) with great problems, eagerly (11) the progressive reforms that promised to bring order out of the (12) of the city.
One of many reforms came (13) the area of public utilities. Water and sewerage systems were usually operated by (14) governments, but the gas and electric networks were privately owned. Reformers feared that the privately owned utility companies would (15) exorbitant (过渡的) rates for these essential services and (16) them only to people who could afford them. Some city and state governments responded by (17) the utility companies, but a number of cities began to supply these services themselves. (18) of these reforms argued that public ownership and regulation would (19) widespread access to these utilities and guarantee a (20) price.

A:secure B:ensure C:reassure D:incur

Throughout the 19th century and into the 20th, citizens of the United States maintained a bias against big cities. Most lived on farms and in small towns and believed cities to be centres of (1) , crime, poverty and moral (2) Their distrust was caused, (3) , by a national ideology that (4) farming the greatest occupation and rural living (5) to urban living. This attitude (6) even as the number of urban dwellers increased and cities became an essential (7) of the national landscape. Gradually, economic reality overcame ideology. Thousands (8) the precarious (不稳定的) life on the farm for more secure and better paying jobs in the city. But when these people (9) from the countryside, they carried their fears and suspicions with them. These new urbanities, already convinced that cities were (10) with great problems, eagerly (11) the progressive reforms that promised to bring order out of the (12) of the city.
One of many reforms came (13) the area of public utilities. Water and sewerage systems were usually operated by (14) governments, but the gas and electric networks were privately owned. Reformers feared that the privately owned utility companies would (15) exorbitant (过渡的) rates for these essential services and (16) them only to people who could afford them. Some city and state governments responded by (17) the utility companies, but a number of cities began to supply these services themselves. (18) of these reforms argued that public ownership and regulation would (19) widespread access to these utilities and guarantee a (20) price.

A:secure B:ensure C:reassure D:incur

(71) is used to ensure the confidentiality, integrity and authenticity of the two end points in the private network. (72) , an application-layer protocol, authenticates each peer in an IPSec transaction.IKE negotiates security policy, determining which algorithm may be used to set up the tunnel. It alsohandles the exchange of session keys used for that one transaction.
Networks that use (73) to secure data traffic can automatically authenticate devices by using (74) , which verify the identities of the two users who are sending information back and forth. IPSeccan be ideal way to secure data in large networks that require secure connections among many devices.
Users deploying IPSec can (75) their network infrastructure without affecting the applications on individual computer. The protocol suite is available as a software-only upgrade to the networkinfrastructure. This alows security to be implemented without costly changes to each computer. Mostimportant, IPSec allows interoperability among different network devices, PCs and other computingsystems.

A:secure B:relation C:script D:strict

(66) is used to ensure the confidentiality, integrity and authenticity of the two end points in the private network. (67) , an application-layer protocol, authenticates each peer in an IPsec transaction. IKE negotiates security policy, determining which algorithm may be used to set up the tunnel. It also handles the exchange of session keys used for that one transaction.
Networks that use (68) to secure data traffic can automatically authenticate devices by using (69) , which verify the identities of the two users who are sending information back and forth. IPsec can be ideal way to secure data in large networks that require secure connections among many devices.
Users deploying IPsec can (70) their network infrastructure without affecting the applications on individual computer. The protocol suite is available as a software-only upgrade to the network infrastructure. This alows security to be implemented without costly changes to each computer. Most important, IPsec allows interoperability among different network devices, PCs and other computing systems.

A:secure B:relation C:script D:strict

(1) is used to ensure the confidentiality, integrity and authenticity of the two end points in the private network. (2) , an application-layer protocol, authenticates each peer in an IPsec transaction. IKE negotiates security policy, determining which algorithm may be used to set up the tunnel. It also handles the exchange of session keys used for that one transaction.
Networks that use (3) to secure data traffic can automatically authenticate devices by using (4) , which verify the identities of the two users who are sending information back and forth. IPsec can be ideal way to secure data in large networks that require secure connections among many devices.
Users deploying IPsec can (5) their network infrastructure without affecting the applications on individual computer. The protocol suite is available as a software-only upgrade to the network infrastructure. This alows security to be implemented without costly changes to each computer. Most important, IPsec allows interoperability among different network devices, PCs and other computing systems.

A:secure B:relation C:script D:strict

(1) is used to ensure the confidentiality,integrity and authenticity of the two end points in the private network． (2) ，an application—layer protocol，authenticates each peer in an IPSec transaction．IKE negotiates security policy，determining which algorithm may be used to set up the tunnel．it alsohandles the exchange of session keys used for that one transaction．
Networks that use (3) to secure data traffic can automatically authenticate devices by using (4) ，which verify the identities of the two users who are sending information back and forth．IPSeccan be ideal way to secure data in large networks that require secure connections among many devices．
Users deploying IPSec can (5) their network infrastructure without affecting the applications on individual computer．The protocol suite is available as a software-only upgrade to the networkinfrastructure．This alows security to be implemented without costly changes to each computer．Mostimportant，IPSec allows interoperability among different network devices，PCs and other computingsystems．

A:secure B:relation C:script D:strict

(71) 　is used to ensure the confidentiality, integrity and authenticity of the two end points in the private network. (72) , an application-layer protocol, authenticates each peer in an IPsec transaction. IKE negotiates security policy, determining which algorithm may be used to set up the tunnel. It also handles the exchange of session keys used for that one transaction.
Networks that use (73) to secure data traffic can automatically authenticate devices by using (74) , which verify the identities of the two users who are sending information back and forth. IPsec can be ideal way to secure data in large networks that require (75) connections among many devices.

A:secure B:relation C:script D:strict

___39___ is used to ensure the confidentiality, integrity and authenticity of the two end points in the private network. ___40___, an application-layer protocol, authenticates each peer in an IPSec transaction. IKE negotiates security policy, determining which algorithm may be used to set up the tunnel. It also handles the exchange of session keys used for that one transaction.
Networks that use ___41___ to secure data traffic can automatically authenticate devices by using by using ___42___, which verify the identities of the two users who are sending information back and forth. IPSec can be ideal way to secure data in large networks that require secure connections among many devices.
Users deploying IPSec can ___43___ their network infrastructure without affecting the applications on individual computer. The protocol suite is available as a software-only upgrade to the network infrastructure. This alows security to be implemented without costly changes to each computer. Most important, IPSec allows interoperability among different network devices, PCs and other computing systems.

A:secure B:relation C:script D:strict

___57___ is used to ensure the confidentiality, integrity and authenticity of the two end points in the private network. ___58___, an application-layer protocol, authenticates each peer in an IPSec transaction. IKE negotiates security policy, determining which algorithm may be used to set up the tunnel. It also handles the exchange of session keys used for that one transaction.
Networks that use ___59___ to secure data traffic can automatically authenticate devices by using by using ___60___, which verify the identities of the two users who are sending information back and forth. IPSec can be ideal way to secure data in large networks that require secure connections among many devices.
Users deploying IPSec can ___61___ their network infrastructure without affecting the applications on individual computer. The protocol suite is available as a software-only upgrade to the network infrastructure. This alows security to be implemented without costly changes to each computer. Most important, IPSec allows interoperability among different network devices, PCs and other computing systems.

A:secure B:relation C:script D:strict