Понимание структурно-смысловых связей в тексте

It was during a radar-related research project around 1946 that Dr. Percy Spencer, while working for Raytheon Corporation, noticed that a candy bar in his pocket melted during the testing of a new vacuum tube called a magnetron. This intrigued Dr. Spencer, A ______. This time he placed some popcorn kernels near the tube and watched B ______.

The next morning Spencer decided to put the magnetron tube near an egg. Spencer and a colleague both watched C ______. Spencer’s colleague moved in for a closer look just as the egg splattered yolk all over his face. Dr. Spencer concluded that if you can cook an egg that quickly, D ______. He began experimenting. Dr. Spencer enclosed the food to be cooked in a metal box that he fed the microwaves into. He had invented what was to revolutionize cooking and form the basis of a multimillion-dollar industry — the microwave oven.

In 1947, Raytheon demonstrated the world’s first microwave oven and called it a Radarange. The first microwave ovens cost between $2,000 and $3,000. Around 1952— 55, Tappan introduced the first home model priced at $1,295. In 1967 Raytheon owned Amana Refrigeration introduced the first countertop microwave oven, E ______.

By 1975, sales of microwave ovens had, for the first time, exceeded those of gas ranges. In 1976, the microwave oven became a more commonly owned kitchen appliance than the dishwasher, F ______. America’s cooking habits were being dramatically changed by the convenience of the microwave oven. Once considered a luxury, the microwave oven has developed into a practical necessity for a fast-paced world of today.

1. as the popcorn sputtered, cracked and popped
2. so he decided to ask for help
3. so he tried another experiment
4. reaching nearly about 52 million US households
5. which was smaller, safer and more reliable than previous models
6. as the egg began to tremor and shake
7. then you could cook other foods as well