问题 单项选择题

以下对IPv6地址的表示中,正确的是()。

A.FF60::2A90:FH:0:4CA2:9C5A:0

B.31DB:0:0:3:0:2A:F:FE80:0

C.::601:4CA2:9C5:B2C7::05D7

D.21AE:D30:0:B3F2:1::/64

答案

参考答案:D

解析:

[考点透解] IPv6的128位地址采用冒号十六进制表示法表示,即按每16位划分为1个位段,每个位段被转换为1个4位的十六进制数,并用冒号“:”隔开。IPv6的128位地址最多可被划分为8个位段,而选项B的“31DB:0:0:3:0:2A:F:FE80:0”共有9个位段,因此选项B的地址表示是错误的。由于选项A的地址表示中出现了字符“H”,它不属于十六进制的有效字符,因此选项A的地址表示也是错误的。 如果IPv6地址中包含了一长串0,则可以使用“双冒号表示法”,进一步简化IP地址表达。但双冒号“::”在一个IPv6地址中只能出现一次。由于选项C的地址表示中出现了两次“::”,因此选项C的地址表示是错误的。 IPv6不支持子网掩码,它只支持前缀长度表示法。前缀是IPv6地址的一部分,用做IPv6路由或子网标识。前缀的表示方法与IPv4中的无类域间路由CIDR表示方法基本类似。IPv6前缀可以用“地址/前缀长度”来表示。例如,选项D的“21AE:D30:0:B3F2:L1::/64”。

阅读理解

信息匹配。

在第1-5题中,Ray, Phil and Adam等人都想去旅游。阅读下面对不同的旅游活动的介绍,

选出符合他们要求的最佳选项,选项中有一个是多余选项。

     The people below all want to go on a short trip and there are descriptions of six trips which a ferry

company is offering. 

       1   .Ray and three of his friends would like to spend a whole weekend driving around in nice scenery and

enjoying some local food.

         2   .Phil and Adam want to go on a comfortable trip which takes them quickly to an interesting city.

Then they want to enjoy at least two days of sightseeing.

        3    . Mike, Kathy and their three children don' t have much money, but they want a special day out this

Saturday. They must be back home by 9 p. m.. 

        4   . Kirsten is a Dutch student who is studying in Scotland. She doesn' t drive, but wants a day trip to

see some beautiful scenery and spend a little time by the sea. 

        5    . Clare and Robert want to enjoy some good food, but would also like to give their two young

children a day to remember. They don't mind if they spend a lot of money.

A

     Marine Life, France

      The chance to experience the oceans of the world. Children will love the observatory (天文台 ),with

water all around them and big fish swimming above their heads! Afterwards you eat at a world-famous local

restaurant before boarding the ferry at 9 p. m. Not cheap, but a great day out!

B

     Amsterdam

     Sail out in the evening and enjoy over 12 hours in the Netherlands, returning the following night. After a

good Dutch breakfast you travel by train direct to the heart of the wonderful city of Amsterdam. The

sightseeing and places to shop will make this a day to remember. Weekends only.

C

     Ireland by Car

     Once you arrive in Ireland you' re quickly on beautiful country roads, with friendly villages where you can

stop for a delicious bite to eat. The special price allows you to take your car and up to five people away for 48

hours, and two night' s hotel accommodation(住宿) can be arranged for a little extra.

D

      French Hypermarket Day Trip

     Whether you want to buy or just look, you'll love this tour. The large Darney shopping center is a

shopper' s dream! You will find a great number of local goods on sale, and clothes and kitchen goods are

excellent value. Free children' s entertainment all day. Leaves 10:OO,back at 19:00.

E

     Belgium by Hydrofoil

     A four-day trip. From England you cross to Belgium in just 100 minutes by hydrofoil! You are served food

and drinks during the crossing, then continue your journey to Brussels, or another beautiful city, on the fast

Belgian railway network. 

F

     Sea and Mountains in Northern Ireland

     Explore the Northern Ireland countryside, including the amazing Mountains of Mourne and the small

seaside holiday town of Newcastle. The ferry leaves the port in Scotland at 7:30 and arrives back at 22:20.

Transport in Northern Ireland is by air-conditioned coach.

单项选择题