For what two purposes does the Ethernet protocol use physical addresses? （）

A . to uniquely identify devices at Layer 2 B . to allow communication with devices on a different network C . to differentiate a Layer 2 frame from a Layer 3 packet D . to establish a priority system to determine which device gets to transmit first E . to allow communication between different devices on the same network F . to allow detection of a remote device when its physical address is unknow

A . Ties a container stack to the deck B . Ties a container to the container below it C . Restrains racking loads D . Restrains the container against horizontal motio

A . Alert the watch officer that a vessel is approaching the preset CPA limit B . Warn of small targets that are initially detected closer than the outer guard zone C . Guard against target loss during critical maneuvering situations D . Sound an alarm for targets first detected within the zone

A . to uniquely identify devices at Layer 2 B . to allow communication with devices on a different network C . to differentiate a Layer 2 frame from a Layer 3 packet D . to establish a priority system to determine which device gets to transmit first E . to allow communication between different devices on the same network F . to allow detection of a remote device when its physical address is unknow

A . To ensure that interference to proprietary communications is minimized B . To ensure that only voice communications can be effected on the distress frequency or channel C . To ensure that a distressed vessel will have a "window" twice each hour for transmitting routine messages D . To ensure that interference on a particular frequency or channel to communications concerning emergency traffic is minimized

A . shut down rogue access points B . configure access points C . discover access points D . inventory access point

A . A dog. B . A doll. C . A guinea pig. D . A smart phone.

A . DSC provides reception of weather and navigational warnings plus search and rescue information B . DSC provides low-cost，routine communications for the vessel operator C . DSC is to be used for transmitting and receiving distress alerts to and from other ships or coast radio stations via radio D . This aids SAR authorities in tracking a vessel's position by satellite

A . audit VoWLAN cell edge coverage B . verify RFID tag coverage by four access points at -75 dBm C . audit microwave oven interference D . audit 802.11a channel 36 utilization E . create test scripts for 802.11n bonded channel throughput test

A．To reveal the sufferings of the native Americans B．To make native Americans better understood by people from other cultures C．To demonstrate philosophical achievements by native Americans D．To explore the origin of native Americans

A．Enlarge their knowledge and learn new skills. B．Catch up the opportunity to get a higher degree. C．Learn more basic knowledge to get a diploma. D．Make themselves live a more comfortable life.

A．I 1.00 pounds. B．9.00 pounds. C．12.00 pounds.

A．To suggest changes to government structure. B．To criticize the practice of slavery. C．To convince the South to surrender. D．To inspire Northerners to support the war.

A.To show people"s behaviors are predictable. B.To describe the nightmare of the story. C.To demonstrate the importance of trust. D.To prove no one can be relied on.

A．To reduce the burden of overseas students. B．To add diversity to study overseas. C．To attract students from undeveloped areas. D．To meet the needs of students home and abroad.

A．The apples and pears might not be so good. B．The apples are not as good as the pears. C．The apples and pears are very good. D．The apples and pears are as good as they look.

A．How predators find, catch, and eat prey B．Behaviors that help prey avoid predators C．Changes in predator and prey populations D．Defensive coloration in prey animals

A．To justify the ways of God to men B．To show how God defeated the rebellious angels C．To prove the superiority of Protestantism over Catholicism D．To show how Adam and Eve made their way out of Eden