Use only one word in each gap. Did you know that microwaves were first used ..........the British Army in the World War II to identify enemy warplanes? In fact, it was ..........accident that made people aware that microwaves could also cook food. In 1945, Percy LeBaron Spencer, .............. work involved the testing of radar waves, became the first person to ........... this connection. ............ day at work, Spencer was standing near a machine which was emitting radio waves. Later .........., when he felt like snack, he reached .......... the chocolate bar he had in his pocket - .......... to find that it had melted! When he thought about it, he realised ......... had happened. The radar waves coming from the machine ......... he had been standing next to had melted his chocolate. Later, experiments showed that radar waves contain microwaves that could heat food .......... faster than traditional ovens. His company went .....
Foreword Bridging rivers, gorges, narrows, straits, and valleys always has played an important role in the history of human settlement. Since ancient times, bridges have been the most visible testimony of the noble craft of engineers. A bridge can be defined in many ways, but Andrea Palladio, the great 16th century Italian architect and engineer, hit on the essence of bridge building when he said "...bridges should befit the spirit of the community by exhibiting commodiousness, firmness, and delight." In more practical terms, he went on to explain that the way to avoid having the bridge carried away by the violence of water was to make the bridge without fixing any posts in the water. Since the beginning of time, the goal of bridge builders has been to create as wide a span as possible which is commodious, firm, and occasionally delightful. Spanning greater distances is a distinct measure of engineering prowess. In terms of engineering, b
or booklet form. The commercial code is a code used in business primarily to save on cable tolls; though some are compiled for private firms, many others are sold to the public and therefore provide no real secrecy. Most ciphers employ a key, which specifies such things as the arrangement of letters within a cipher alphabet, or the pattern of shuffling in a transposition, or the settings on a cipher machine. If a word or phrase or number serves as the key, it is naturally called the keyword or keyphrase or keynumber. Keys exist within a general system and control that system's variable elements. For example, if a polyalphabetic cipher provides 26 cipher alphabets, a keyword might define the half dozen or so that are to be used in a particular message. Codewords or codenumbers can be subjected to transposition or substitution just like any other group
percent is consumed in multi-family dwellings such as apartments, and 5 percent is consumed in mobile homes. Picture 2.4. Energy use in different types of homes More than half of the energy used for heating in single-family homes (either attached or detached) is natural gas, about one-fourth is electricity, and one-tenth is fuel oil (heating oil). Over three-fourths of single-family homes have some type of air conditioning. Most single-family homes have a washing machine and a dryer. Among Single-Family Dwellings: In 2005, for the Main Heating Fuel and Equipment: · 56% use Natural Gas · 26% use Electricity · 7% use Fuel Oil · 6% use LPG · 1% use Kerosene 84% of single family homes have air conditioning (central system, wall/window units or both). For Appliances: · 95% have a clothes washer · 92% have a clothes dryer 7 · 74% have a personal computer
Table of contents 1. Introduction 2. History 2.1. Early Hospitals 2.2 Recent developments 3. The National Health Service 4. Diseases 5. First Aid 6. Medicine and elements of medical care 7. Doctors 8. Ways of keeping health 9. Conclusion 10.Used materials 1. Introduction The human body is just like a machine with many parts. Each part has a special job, and all the parts work together to keep you alive and healthy. Good health is one of the most important things in life. There are certain things we can do to stay healthy. We should eat a balanced diet that includes the right kinds of food and drink plenty of clean, fresh water. We should exercise regularly, strengthening our muscles and keeping us in shape. Exercise helps the blood circulate around our bodies, cleaning
Britain History Pre-Norman Britain The Iberians brought their metal-working skills and the first real civilization to Britain in the third millennium B.C and were overrun by various Celtic invasions that began in the 8th century. The Celts introduced their tribal organization and an early form of agriculture before they were forced westward by the Roman invasion. Forms of Celtic language are still spoken in Britain. Romans (with Julius Caesar in the head of them) first tried to occupy Britain in 55 B.C., but there was a rebellion in Gaul so they had to leave to fight against it. Next time they came in 43 A.D. and their leader was Emperor Claudius. Romans brought a lot with them. Their brought paved roads, the sites of important cities, the seeds of Christianity, the Roman law, Roman baths, language and advanced civilization. They also built Hadrian's Wall in 122 A.D. Romans occupied Britain for four centuries. The Roman wa
BOOKS (From Wikipedia, the free encyclopedia) A book is a set or collection of written, printed, illustrated, or blank sheets, made of paper, parchment, or other various material, usually fastened together to hinge at one side. A single sheet within a book is called a leaf, and each side of a leaf is called a page. A book produced in electronic format is known as an electronic book (e-book). Books may also refer to works of literature, or a main division of such a work. In library and information science, a book is called a monograph, to distinguish it from serial periodicals such as magazines, journals or newspaper. The body of all written works including books is literature. In novels and sometimes other types of books (e.g. biographies), a book may be divided into several large sections, also called books (Book 1, Book 2, Book 3, etc.). A lover of books is usually referred to as a bibliophile, or, more informally, a bookworm. A store where books are bought and sold is a bookstore
West and East and began spreading rapidly. Workers' movements emerged and the first strike was organised in the Narva Kreenholm factories (1870). On the initiative of politically radical students who had come to (the now Russian-language) Tartu University from all over the tsarist empire, the first Marxist organisations sprang up in the 1880s. During the ever more vigorous period of industrialisation in the second half of the 19th century, large textile, metal and machine works, as well as timber, paper, cellulose and foodstuff enterprises and factories were established in Estonia. A railway network connecting Estonia with the domestic market of the Russian Empire was built. The TallinnSt Petersburg line was
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