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 Secrets of Web Travel Sites

Booking a trip on an online travel siteis convenient, but comes with its own set of problems.

1 They who's on a Mac and who's on a PCand who's going to spend more.

Last year, US travel research companyOrbitz tracked people's online activities to test out whether Mac users spendmore on travel than PC users. On average, Mac users lay out US$20-30 more pernight on hotels and go for more stars. according to the Wall Street Journal. Asa result, online• travel sites show these users more expensive travel optionsfirst. To avoid inadvertently paying more, sort results by price.

 Their software doesn't always hook up to thehotel's system.

A guaranteed reservation is almostimpossible to come by anywhere — but the risk of your flight or hotel beingoverbooked increases with third-party providers. The middle-man's softwareisn't immune to system errors, so always call the hotel or airline to make sureyour booking was processed.

 Don't be fooled by packages: Often, they'relow-end items grouped together.

Ever notice how travel sites recommend ahotel, a rental car, and tour package all in one click? These deals usuallyfeature travel that no one wants, like flights with multiple layovers.

Check the fine print.

 You could miss out on loyalty points.

Third-party providers can get betweenyou and frequent flyer miles or points. Many hotel loyalty programmes don'trecognise external sites, others award only minimum points and exclude specialoffers, like double points on hotel stays.

 Once your trip is purchased, you're on yourown.

An online travel agency can't provideassistance the same way an agent can if a flight is cancelled or a room issubstandard. Basically, when you arrive at the airport or hotel, you're justanother client who booked at the lowest rate.

设N_A为阿伏加德罗常数，下列叙述中正确的是（   ）

阅读下面的古诗文，完成小题

    邓训字平叔，少有大志。显宗即位，初以为郎中。训乐施下士，士大夫多归之。

    章和二年，护羌校尉张纡诱诛烧当种羌迷吾①等，由是诸羌大怒，谋欲报怨，朝廷忧之。公卿举训代纡为校尉。诸羌激忿，遂相与解仇结婚，交质盟诅，众四万余人，期冰合渡河攻训。先是，小月氏胡②分居塞内，胜兵者二三千骑，缘勇健富强，每与羌战，常以少制多。虽首施两端，汉亦时收其用。

    时迷吾子迷唐，别与武威种羌合兵万骑，来至塞下，未敢攻训，先欲胁月氏胡。议者咸以羌胡相攻，县官之利。训曰：“不然。今张纡失信，众羌大动，经常屯兵，不下二万，转运之费，空竭府帑，凉州吏人，命县丝发。原诸胡所以难得意者，皆恩信不厚耳。今因其迫急，以德怀之，庶能有用。”遂令开城，悉驱群胡妻子内之。由是湟中诸胡皆言“汉家常欲斗我曹，今邓使君待我以恩信，开门内我妻子，乃得父母。”咸欢喜叩头曰：“唯使君所命。”训遂抚养其中少年勇者数百人，以为义从。

    永元四年冬，病卒官，时年五十三。胡人爱惜，旦夕临者日数千人。

（选自《后汉书•邓寇列传第六》，有删改）

【注】①烧当种羌迷吾：烧当种羌，与后文的“武威种羌”均为当时的羌族部落名称。迷吾，部族首领。②小月氏胡：西北少数民族。