3 Complete the text with the words from exercise 2. Rugby is the national sport of Wales. There are 15 players in a rugby team. All rugby players
wear (1)
shirts and special (2).
on their feet. Some players
wear (3)
on their heads. The two teams play a rugby match on a (4)
The match lasts for 80 minutes. The (5)
isn't round like a football. It's shaped
like an egg
(1)
1. When you drop oil in water, it floats.
2. If we had enough money, we would buy a new computer.
3. You will get higher marks if you study more.
4. If the weather was a bit warmer, we would go on a picnic today.
5. Sue will forgive you if you apologise to her.
6. If I had known it was a secret, I wouldn't have told anyone.
7. If I had more time, I would take music lessons.
If Jack had trained harder, he could have got the first place in the competitions.
(2)
1. win
2. club
3. sport
4. climbing
(3)
1. Nick was too tired to go climbing, so he decided to spend a day on the golf court/ course.
2. The outdoor ice-skating rink/pitch is one of the biggest attractions of our town.
3. Your paintings are brilliant. You should participate in the school’s painting competition/championship.
4. His driving coach/instructor usually gave him very useful advice on how to park on narrow streets.
5. Mr. Brown’s technical/physical knowledge of computers enables him to analyse complex sports statistics.
6. Jenny bought a pair of new skis/skates, as her old ones had fallen apart.
(4)
1. You won't be able to go to the sports competitions unless you finish your homework first.
2. When spring approaches, the weather becomes warmer and the days get longer.
3. You cannot get good seats at the stadium if you don't buy your tickets ahead of time.
4. Grandma brings us lots of presents when she comes for a visit.
5. If you like playing tennis, you'll probably like playing squash. They are very similar.
Currently, thanks to the introduction of GPS, accurate and inexpensive navigation receivers are widely used. How do these little smart assistants know where you are?
The basic principle underlying the entire GPS system is simple and has long been used for navigation and orientation: if you know exactly the location of a reference point and the distance to it, you can draw a circle (in the 3-dimensional case - a sphere), on which should be the point of your position. In practice, if the above distance, i.e. radius is large enough, you can replace the arc of a circle with a straight line segment. If you draw several of these lines corresponding to different reference points, then the point of their intersection will indicate your location. In GPS, the role of such benchmarks is played by two dozen satellites, each moving in its own orbit at an altitude of about 17,000 km above the surface of the Earth. The speed of their movement is very high, but the parameters of the orbit and their current location with high accuracy are known to on-board computers.
An important part of any GPS navigator is a regular radio receiver operating at a fixed frequency and constantly “listening” to the signals transmitted by these satellites. Each of the satellites constantly emits a radio signal, which contains data on the parameters of its orbit, the state of the onboard equipment and the exact time. Of all this information, the exact flight time data is the most important: the GPS receiver, using the integrated processor, calculates the time interval between sending and receiving the signal, then multiplies it by the speed of propagation of radio waves, etc. recognizes the distance between the satellite and the receiver. The result of subsequent calculations are the coordinates of your location.
Объяснение:
В настоящее время благодаря внедрению системы GPS получили широкое распространение точные и недорогие навигационные приемники. Каким же образом эти маленькие "умные" узнают, где Вы находитесь?
Основной принцип, лежащий в основе всей системы GPS, прост и давно используется для навигации и ориентирования: если Вы точно знаете местоположение какого-либо реперного ориентира и расстояние до него, то можно начертить окружность (в 3-х мерном случае - сферу), на которой должна быть расположена точка Вашего положения. На практике, если вышеуказанное расстояние, т.е. радиус, достаточно велик, то можно заменить дугу окружности отрезком прямой линии. Если провести несколько таких линий, соответствующих разным реперным ориентирам, то точка их пересечения укажет Ваше местоположение. В GPS роль таких реперов играют две дюжины спутников, движущихся каждый по своей орбите на высоте около 17 000 км над поверхностью Земли. Скорость их движения весьма велика, однако параметры орбиты и их текущее местонахождение с высокой точностью известны бортовым компьютерам.
Важной частью любого GPS-навигатора является обычный радиоприемник, работающий на фиксированной частоте и постоянно "прослушивающий" сигналы, передаваемые этими спутниками. Каждый из спутников постоянно излучает радиосигнал, в котором содержатся данные о параметрах его орбиты, состоянии бортового оборудования и о точном времени. Изо всей этой информации данные о точном бортовом времени являются наиболее важными: GPS-приемник с встроенного процессора вычисляет промежуток времени между посылкой и получением сигнала, затем умножает его на скорость распространения радиоволн и т.о. узнает расстояние между спутником и приемником. Результатом последующих вычислений являются координаты Вашего местоположения.