（本小题满分12分）
某公司销售一种新型节能产品，现准备从国内和国外两种销售方案中选择一种进行销售．
若只在国内销售，销售价格y（元/件）与月销量x（件）的函数关系式为y =x＋150，
成本为20元/件，无论销售多少，每月还需支出广告费62500元，设月利润为w内（元）（利润 = 销售额－成本－广告费）．
若只在国外销售，销售价格为150元/件，受各种不确定因素影响，成本为a元/件（a为
常数，10≤a≤40），当月销量为x（件）时，每月还需缴纳x2 元的附加费，设月利润为w外（元）（利润 = 销售额－成本－附加费）．
（1）当x = 1000时，y ="        " 元/件，w内 ="        " 元；
（2）分别求出w内，w外与x间的函数关系式（不必写x的取值范围）；
（3）当x为何值时，在国内销售的月利润最大？若在国外销售月利润的最大值与在国内销售月利润的最大值相同，求a的值；
（4）如果某月要将5000件产品全部销售完，请你通过分析帮公司决策，选择在国内还是在国外销售才能使所获月利润较大？
参考公式：抛物线的顶点坐标是．

阅读理解

Oyster

What is an Oyster card?

    Oyster is the easiest way to pay for journeys on the bus, Tube, tram, DocklandsLight Railway (DLR), London Overground and National Rail journeys in London Youcan store your travel cards, Bus & Tram Pass, season tickets and credit topay for journeys as you go.

Where to get an Oyster card?

There are a number of ways for you to get an Oyster card:

• At over 3,900 Oyster Ticket stops

• At Tube and London Overground station ticket offices

• At some National Rail stations

• At London Travel information Centres

• Online at tfl. gov. uk/oyster

How to use an Oyster card?

    To pay the correct fare on the Tube , DLR, London Overground andNational Rail services, you must always touch in on the yellow Oyster cardreader at the start of your journey, and touch out at the end. If you don't, amaximum cash Oyster fare will be charged. When using the bus or tram, you mustonly touch in at the start, but not at the end of your journey.

   What happens if I don't visit London very often?

    Don't worry. Any pay as you go credit on your card will notexpire (过期), so you cankeep it for your next visit or lend it to a friend.

Fares

Traveling by Tube from Central London (Zone l)to Heathrow (Zone6)

Adult Oyster single fare

£ 4. 20 Monday to Friday 06:30 - 09:30 and 16:00 - 19:00

£ 2. 70 at all other times including public holidays

Adult single cash fare £ 5.00

For further information，visit tfl.gov.uk /fares.

下图是张老师上课时用的一张幻灯片。请你根据内容为其拟定一个最适当的标题（    ）

如图，点C为线段AB的黄金分割点（AC＞BC），已知AC=4，则AB=____．

下列有关化学研究的说法正确的是