What is true of using group functions on columns that contain NULL values?（）

A . You must use Oracle predefined names to identify raw partitions that will hold OMF structures.  B . You must define directories for two online redo log groups and three copies of the control file.  C . If your CREATE DATABASE command fails, any OMF database files that have already been created will be dropped automatically.  D . You must use only OMF data files when adding new tablespaces or data files to your database in the future.

A . A bitt B . A bulkhead C . A V-spring D . A fishplate

A . Switches take less time to process frames than hubs take. B . Switches do not forward broadcasts. C . Hubs can filter frames. D . Using hubs can increase the amount of bandwidth available to hosts. E . Switches increase the number of collision domains in the network.

A . It ignores duplicates. B . It prevents character set translation on import. C . It allows rows to be inserted into a table that already exists. D . It ignores storage parameters in the DML executed during import.

A . Devices use DHCP to request their VLAN. B . Attached devices are unaware of any VLANs. C . Devices are assigned to VLANs based on their MAC addresses. D . Devices are in the same VLAN regardless of which port they attach to.

A . It provides a graphic display to emphasize which vessel is on a collision course B . In the true presentation，it provides a quick visual check to determine if a vessel has changed course C . The display is one of the primary inputs and must be in use when using the trial maneuver capability D . It provides a graphic display of a target vessel's relative course，speed，and CPA

A . They are designed to provide for the flow of small volumes of tank atmospheres caused by thermal variations in a cargo tank B . They should operate in advance of the pressure/vacuum breakers C . They should be kept in good working order by regular inspection and cleaning D . All of the above

A . It must have the UNIQUE attribute. B . It cannot be created explicitly by the user. C . It must have the UNIQUE and CLUSTER attributes. D . It must have the UNIQUE WHERE NOT NULL attribute.

A . It is mainly used in Intra-AS MPLS VPLS deployments and is configured at the ASBR to avoid misconfiguration of the Route Target assignment for VPN configurations B . It is mainly used in Inter-AS MPLS VPN deployments and is configured at the ASBR to avoid misconfiguration of the Route Target assignment for VPN configurations C . It is mainly used in Intra-AS MPLS VPLS deployments and is configured at the Router Reflectorto avoid misconfiguration in Route Target assignment for VPN configurations D . It is mainly used in Inter-AS MPLS VPLS deployments and is configured at the Router Reflectorto avoid misconfiguration of the Route Target assignment for VPN configurations E . It is mainly used in Inter-AS MPLS VPLS deployments and is configured at the PE router to avoid to misconfiguration of the Route Target assignment for VPN configuratio

A . Redo is not generated while performing conventional path loads. B . Only PRIMARY KEY， UNIQUE KEY， and NOT NULL constraints are checked. C . No exclusive locks are acquired when the conventional path loads are performed. D . Instead of performing transactions， SQL*Loader directly writes data blocks to the data files. E . INSERT triggers are disabled before the conventional path load and reenabled at the end of the load

A . GM B . KG C . KM D . GZ

A . Mention signal stations and ice，storm，traffic and port signals B . Give the international numbers of lights C . Give the correction of the lights and fog signals D . Give the information on the lights and fog signal

A . QoS preclassification is only supported on generic routing encapsulation （GRE） and IPsec VPNs B . QoS preclassification is not required in Layer 2 Tunneling Protocol （L2TP）， Layer2 Forwarding （L2F）， and Point-to-Point Tunneling Protocol （PPTP） VPNs C . QoS preclassification is supported on IPsec AH VPNs， but not on IPsec ESP VPNs D . the QoS-for-VPNs feature （QoS preclassification） is designed for VPN transport interfaces E . with IPsec tunnel mode， the type of service （ToS） byte value is copied automatically from the original IP header to the tunnel header

A . decreases the amount of flows   B . collects information about callers to agents   C . creates a framework for CRS Server status reporting  D . decreases latency through increased bandwidth on CRS Server   E . provides more efficient management of flows that are called by multiple other flow

A．It is the highest maintain in Washington DC. B．It is an active volcano. C．It has erupted only once. D．The new form. of Mount Rainer results from glacial ice. 此题为多项选择题。

A.It is used to transmit global monitoring messages. It needs to be declared in the OSPF configuration. B.Indicate that the next hop of the tunnel needs to be encapsulated in the VLAN corresponding to the interface IP and the corresponding MAC address should be encapsulated. C.Indicate the start point and end point of the tunnel service. D.This address has nothing to do with the port. The network element still can be pinged successfully if it has one physical port connected.

A．It is a cathedral theatre. B．All performances here are amateur and half-professional. C．People remember the performances here long after the companies have left. D．A dozen of the world top performers come here to perform. every year.

A．People use them to reflect their fancy. B．People use them to reverse irreversible things. C．People use them to undo past events in their life. D．People use them in the interfaces of the virtual worlds.

A．This article starts with a report on one of the beach protests which remains the part of nationwide grassroots protests against offshore drilling． B．Jane Barry was very efficient in organizing this 15-minute beach protest since the group could end up in some 200 people chanting their demand to stop offshore drilling． C．Dave Rauschkolb started this movement originally because of the BP oil spill and its severe consequences in the aftermath． D．The objective of this movement, according to Rauschkolb, is to persuade politicians involved into supporting the idea of not resorting to offshore drilling．