海船船员考试
单选题After a collision or accident involving an uninspected vessel，regulations require that the operator assist persons affected，but only if the operator can do so without（）.A further damaging the other vesselB undue delayC serious danger to his or her own
题目
further damaging the other vessel
undue delay
serious danger to his or her own vessel
creating a panic on either vessel
相似问题和答案
第1题：
A. off
B.up
C. down
D. in
第2题：
●Let us now see how randomization is done when a collision occurs.After a(71),time is divided into discrete slots whose length is equal to the worst-case round-trip propagation time on the ether(2τ). To accommodate the longest path allowed by Ethernet, the slot time has been set t0 512 bit times, or 51.2μsec.
After the first collision, each station waits either 0 or l (72) times before trying again. If two stations collide and each one picks the same random number, they will collide again. After the second collision, each one picks either 0,1,2,or 3 at random and waits that number of slot times. If a third collision occurs (the probability of this happening is 0.25), then the next time the number of slots to wait is chosen at (73) from the interval 0 to 23-1.
In general, after i collisions,a random number between 0 and 2i-1 is chosen, and that number of slots is skipped. However, after ten collisions have been reached, the randomization (74) is frozen at a maximum of 1023 slots. After 16 collisions, the controller throws in the towel and reports failure back to the computer. Further recoveryis up to (75 )layers.
(71) A．datagram
B．collision
c．connection
D． service
(72) A．slot
B．switch
C．process
D．fire
(73) A．rest
B．random
C．once
D．odds
(74) A．unicast
B．multicast
C．broadcast
D．interval
(75) A．local
B．next
C．higher
D．lower
第3题：
A. came up
B. came to
C. came down
D. came over
第4题：
He carried on( )after his accident.
A. to work
B. work
C. working
D. worked
第5题：
A. down
B. up
C. off
D. in
第6题：
On a half-duplex Ethernet LAN, two hosts attempt to send data simultaneously, resulting in a collision. Following this collision, what will the hosts do? (Select all valid answers)
A. The destination host sends a request to the source for retransmission.
B. The jam signal indicates that the collision has been cleared.
C. The hosts will attempt to resume transmission after a time delay has expired.
D. An electrical pulse indicates that the collision has cleared.
E. The router on the segment will signal that the collision has cleared.
F. The hosts will do nothing, as the higher layers are responsible for data error correction and re-transmission.
C 解析：Explanation:
When a host on an Ethernet LAN has information to send, the following steps are taken:
1. A device with a frame. to send listens until Ethernet is not busy.
2. When the Ethernet is not busy, the sender begins sending the frame.
3. The sender listens to make sure that no collision occurred.
4. Once the senders hear the collision, they each send a jamming signal, to ensure that all stations recognize the collision.
5. After the jamming is complete, each sender randomizes a timer and waits that long.
6. When each timer expires, the process starts over with step 1.
第7题：
He _____to hospital after the accident.
A.took
B.was taken
C.was taking
第8题：
A.dismissed
B.discussed
C.disappeared
D.discovered
第9题：
Which two statements describe the operation of the CSMA/CD access method, which is in use on the Ezonexam network? (Choose two)
A. After a collision, the station that detected the collision has first priority to resend the lost data.
B. In a CSMA/CD collision domain, stations must wait until the media is not in use before transmitting.
C. In a CSMA/CD collision domain, multiple stations can successfully transmit data simultaneously.
D. The use of hubs to enlarge the size of collision domains is one way to improve the operation of the CSMA/CD access method.
E. After a collision, all stations run a random backoff algorithm. When the backoff delay period has expired, all stations have equal priority to transmit data.
F. After a collision, all stations involved run an identical backoff algorithm and then synchronize with each other prior to transmitting data.
B,E 解析：Explanation:
Ethernet networking uses Carrier Sense Multiple Access with Collision Detect (CSMA/CD), a protocol that helps devices share the bandwidth evenly without having two devices transmit at the same time on the network medium. CSMA/CD was created to overcome the problem of those collisions that occur when packets are transmitted simultaneously from different nodes. And trust me, good collision management is crucial, because when a node transmits in a CSMA/CD network, all the other nodes on the network receive and examine that transmission.
Only bridges and routers can effectively prevent a transmission from propagating throughout the entire network! So, how does the CSMA/CD protocol work? Like this: when a host wants to transmit over the network, it first checks for the presence of a digital signal on the wire. If all is clear (no other host is transmitting), the host will then proceed with its transmission.
But it doesn't stop there. The transmitting host constantly monitors the wire to make sure no other hosts begin transmitting. If the host detects another signal on the wire, it sends out an extended jam signal that causes all nodes on the segment to stop sending data (think, busy signal). The nodes respond to that jam signal by waiting a while before attempting to transmit again. Backoff algorithms determine when the colliding stations can retransmit. If collisions keep occurring after 15 tries, the nodes attempting to transmit will then time out.
第10题：
After a collision or accident involving an uninspected vessel，regulations require that the operator assist persons affected，but only if the operator can do so without ______.
A.further damaging the other vessel
B.undue delay
C.serious danger to his or her own vessel
D.creating a panic on either vessel