Which description is correct for a private VLAN community port with respect to Layer 2 communications？（）   

A . The buffer is currently being accessed. B . The buffer is empty and has not been used. C . The contents of the buffer have changed and must be flushed to the disk by the DBWn process.  D . The buffer is a candidate for immediate aging out and its contents are synchronized with the block contents on the disk.

A .  It will only become active after a software failure. B .  It will only become active after a hardware failure. C .  It requires that Cisco NSF be enabled in order to work successfully. D .  It synchronizes the MAC·， FIB·， and adjacency tables between Active and Standby RouteProcessors.

A .  It will only become active after a software failure B .  It will only become active after a hardware failure C .  It requires that Cisco N3F· be enabled in order to work successfully D .  It synchronizes the MAC·， FIB·， and adjacency tables between Active and Standby Route Processor

A . All traffic destined for network 172.16.150.0 will be denied due to the implicit denyall. B . All traffic from network 10.0.0.0 will be permitted. C . Access-list 101 will prevent address spoofing from interface E0. D . This ACL will prevent any host on the Internet from spoofing the inside network address as the sourceaddress for packets coming into the router from the Internet.

A . MD5 has been used by BGP to encrypt BGP update packets. B . BGP uses a message-digest algorithm to authenticate BGP peers C . A plain-text password authentication is an option of BGP authentication D . EBGP peers authentication is faster than IBGP peers authentication E . BGP uses public key and private key to authenticate BGP peers.

A . The configuration on the FTP server is copied to RAM B . The command is not valid on a Cisco router C . The configuration file in RAM is copied to an FTP server D . The configuration file in NVRAM is copied to an FTP server E . The configuration on the FTP server is copied to NVRAM F . The configuration will be copied from NVRAM to an FTP server with a filename of Kevi

A . They use the same key for encryption and decryption of data. B . They use different keys for decryption but the same key for encryption of data. C . They use different keys for encryption and decryption of data. D . They use the same key for decryption but different keys for encryption of data.

A . optical technology for transmitting up to 32 channels over multiple fiber strands B . optical technology for transmitting up to 16 channels over multiple fiber strands C . a WDM system that is compatible with EDFA technology D . a technology for transmitting more closely packed optical signals using more sophisticated transceiver designs than CWDM .

A . IP source address is forged B . IP destination address is forged C . IP TCP source port is forged D . IP TCP destination port is forged E . None of above

A．It describes a story that happens in the future. B．One of the features in the novel is the misuse of language. C．It is the most famous detective novel in the world. D．It was written in the 20th century.

A．A.Better cell HO B．B.Emergency HO C．C.Low battery HO D．D.Power budget HO

A．A.A prepreg is the impregnated fiber reinforcement with a resin matrix. B．B.The fiber reinforcement in a prepreg only exists in unidirectional forms C．C.The fiber reinforcement in a prepreg can exist in unidirectional or fabric forms D．D.The resins for a prepreg includes thermoset and thermoplastic resins

A．Signal-regulated secretion requires the participation of clathrin, whereas continuous secretion is not required B．The specificity of the transporter is regulated by clathrin and adaptin in the composition of the vesicles C．Receptor-mediated transport needs protein or protein complex to associate with a specific receptor in the cell membrane D．Insulin secretion is endocytosis

A.Pre-Islamic Arabia was backward and underdeveloped. B.Pre-Islamic Arabs showed no interest in sea trade. C.Mecca was one of the most important trading centers. D.Pre-Islamic Arabs would pray to their tribal gods or goddesses.

A．The amplitude of the end plate potential is proportional to the amount of Ach released B．Some of them are depolarized, some of them are hyperpolarized C．is attributed to the Ca2+ influx at the end plate D．propagate on the end plate without the decrement of the amplitude E．followed by refractory period

A．A.The resin matrix for thermoset prepregs is partially cure B．B.The resin matrix for thermoset prepregs is fully cross-linked C．C.The thermoset prepregs are dramatically different from thermoplastic prepregs. D．D.More commonly used in prepreg composite manufacturing is thermoset prepregs.