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    With fuel costs rising and airlines finding more fees to impose (强加,征税)on travelers every day, airfare isn’t getting any cheaper. Since you can’t drive to all your dream destinations, flying is the only way to go sometimes and, undeniably, the fastest. Luckily, there are plenty of ways to find the most affordable fares and also avoid paying as many extra charges as possible when you plan ahead.

    Get the best fare. Airlines put out their fare sales on Tuesday morning, making this day the best day to book a flight for less.

    Fly during the least popular times. Tuesday, Wednesday and Saturday are the slowest days to fly, which means cheaper deals than the rest of the week. You can also find reduced rates on early morning flights, since many people don’t like to get up before the sun to get to the airport. Earlier boarding times can also considerably cut down your chances of getting bumped on an overbooked flight or delayed because of other delayed flights or mechanical issues.

    Choose your seat later. Some airlines charge you to pick your seat when you book online, adding even more to the bottom line of your ticket cost. If you show up early on your travel day, you can still get suitable seats. Some of the best seats get held back until flight day, unless others are willing to pay extra for them ahead of time, so you still have the chance at one of those.

    Fly on holidays. You already know that summer is the most expensive time to fly, and even though most other times are more affordable, the days surrounding holidays can be crazy. Save big if you’re willing to travel on major holidays, such as Thanksgiving and Christmas.

    Don’t wait until the last-minute to book. Many travelers don’t know that there’s a sweet spot for booking and getting the best price on your tickets. Book too early or too late and you could end up paying more than you need to. The best time to book is between three months and six weeks from when you want to travel.

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同类题2

绿萝属于半阴生藤蔓植物,喜湿润环境.下图为一株绿萝植物被放置于黑暗中3d,标号A至E的5张大小相同的叶片被取下置于黑暗中进行实验.请分析回答:


A

B

C

D

E

在黑暗中处理

下表皮浸入5%蔗糖溶液(去掉叶柄并用胶带封口)


上表皮浸入5%蔗糖溶液(去掉叶柄并用胶带封口))

2d后脱色并用碘溶液测试这些叶片


(1)从图中可得出的结论是(写出2条): ____ 

(2)有同学想证明这种植物上表皮的气孔少于下表皮,于是将E叶片叶柄去掉并用胶带纸封口,将上表皮朝下放在5%蔗糖溶液中,下表皮朝上不接触蔗糖溶液.2d后脱色并用碘液处理.

实验假设是:____

预期实验现象是:____ .

(3)研究发现,当土壤干旱时,绿萝根细胞会迅速合成某种化学物质x.有人推测根部合成X运输到叶片,能调节气孔的开闭.他们做了如下实验:从同一植株上剪取大小和生理状态一致的3片绿萝叶,分别将叶柄下部浸在不同浓度X的培养液中.一段时间后,测得的有关数据如下表所示:(注:气孔导度越大,气孔开启程度越大)

分组

测量指标

培养液中X的浓度/mol•m3

5×105

5×104

5×103

叶片中X的浓度/

mol•g1(鲜重)

2.47

2.97

9.28

叶片中的气孔导度/

mol•m2•a1

0.54

0.43

0.27

①以上方案有两处不完善的地方,请指出来并加以修正.

a.____ .

b.____ .

②叶片的蒸腾速率可反映气孔的开放程度,若表中数据为方案完善后得到的结果,那么可推测,随着培养液中X的浓度增大,叶片蒸腾作用强度____