液体石蜡属于A．B．C．D．E．

●A firewall is a (68) system designed to (69) all organization,s network aga-inst threats.

(68) A．operating

B．programming

C．security

D．service

(69) A．prevent

B．protect

C．develop

D．exploit

A firewall is a(68)system designed to(69)all organization, s network against threats.

A．operating

B．programming

C．security

D．service

●A firewall is a (68) system designed to (69) all organization,s network aga-inst threats.

(68) A．operating

B．programming

C．security

D．service

(69) A．prevent

B．protect

C．develop

D．exploit

A firewall is a(1)system designed to(2)an organization's network against threats.

A．operating

B．programming

C．security

D．service

●A firewall is a (71) system designed to (72) an organization′s network against threats.

(71) A．operating

B．programming

C．security

D．data

(72) A．prevent

B．protect

C．examine

D．exploit

A firewall is a(72)system designed to(73)an organization's network aga-inst threats.

A．operating

B．programming

C．security

D．service

A firewall is a(72)system designed to(73)an organization's network aga-inst threats.

A．operating

B．programming

C．security

D．service

A firewall is a(71)system designed to(72)an organization's network against threats.

A．operating

B．programming

C．security

D．data

A firewall is a security system designed to(62) an organization's network against(63)．

A．prevent

B．protect

C．develop

D．exploit

●The typical firewall consists of two packet filters and a (an) (68) ．

(68) A．router

B．bridge

C．application

D．server