How many London underground lines are there? In which two ways are the lines distinguished from each other?

Presenter: Welcome to this latest lecture on living in London. Today,
we’re going to look at transport and I’d like to start with the London underground
system—also called "the tube" because of the shape of the tunnels.
First, you need to learn your lines. There are 12 different lines, each with its     Q11
own name, for example, the Piccadilly line, the Circle line. Each line is a different       Q12
colour on the map of the underground system. You can find the map
in the ticket hall at each underground station, and usually on the platforms
as well. Sections of the map are also displayed in the carriages of the underground trains. Before you begin, it helps to know which line you are starting
on and on which line your destination can be found. If they are on different
lines, look at the map to see where the two lines cross, and note the name of
the station where they meet—that is where you have to change trains. If the
two lines do not cross, keep looking until you find a third line that crosses
both of the other two. Then you will need to change trains twice.
  You can buy a ticket from one of the automatic machines or from the
ticket office. Either way, you need to know the name of the station you are
going to. You also need to know whether you want a "single" ticket, which
is valid just to get you to your destination or a "return", which gets you there
and back again. Fares are based on a zone system: the more zones you travel
through, the more expensive your fare is. There are six zones, with zone 1
covering central London and zone 6 covering the outskirts of the system,            Q13
including, for example, Heathrow Airport. Most of the underground maps
show which stations are in which zones. A single ticket for travel through all
six zones currently costs ￡4. Depending on how far you are travelling and
how many journeys you need to make, it may be cheaper to buy a one-day           Q14
Travel card, which gives you unlimited travel on all London underground
and bus services the day you buy it. A one-day Travel card covering all six
zones currently costs ￡8. You can also buy an Oyster card. This is the best
option if you are going to be in London for a long time. You get a discount          Q15
on all tickets—usually about 10%-and you don’t have to queue to buy tickets.
Just buy credit for your card and then use it as directed when you enter
and leave underground stations at the start and finish of your journeys.   
  At underground stations you must pass through an automatic gate. Put          Q16
your ticket into the slot to the right of the gate. When the gate opens, pass
through. As you pass through, your ticket will pop up from another slot on
the top. Pull your ticket out and take it with you; you need it at the end of
your journey. This is the same procedure for Travel cards. With Oyster cards,
you hold your card over the card reader at special automatic gates. If you            Q17
have baggage with you, you can go through a special, larger gate where you
can pass through more easily. Show your ticket to an attendant and ask him
or her to let you through this gate.
  Most stations have long escalators leading to and from the trains. Try     Q18
to stand to the right-hand side, leaving space for people to walk past you on
the left. When changing trains, get off at the station where the line you are on
crosses the line you need. Follow the signs for the line you need, and the direction     Q19
you want to go in. When you leave the system, you must pass through an
automatic gate again to leave the station. Put your ticket in the slot as before.
If you bought a return ticket or a Travel card, your ticket will pop up for you to
collect again, so that you can use it later. If you bought a single ticket, or if you
are on the return trip of your return ticket, your ticket will stay in the machine.
  To find out more about the London underground, check the official
website: www. thetube.com. This site also has the map and information in numerous     Q20
foreign languages. Now, let’s move on to ...