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e beautiful to look at, but they can destroy ships at sea, as well as houses and buildings near the shore. What causes waves? Most waves are caused by winds blowing over the surface of the water. The sun heats the earth, causing the air to rise and the winds to blow. The winds blow across the sea, pushing little waves into bigger and bigger ones.The size of a wave depends on how strong the wind is, how long it blows, and how large the body of water is. In a small bay big waves will never build up. But at sea the wind can build up giant powerful waves. A rule says that the height of a wave (in meters) will usually be more than onetenth of the wind’s speed (in kilometers). In other words, when the wind is blowing at 120 kilometers per hour, most waves will be about twelve meters. Of course, some waves may bine to form giant waves that are higher. In 1993 the United States Navy reported the largest measured wave in history. It rose in the Pacific Ocean to a height of thirtyfour meters. can guess the height of a wave by knowing__________. A. how fast the wind is blowing B. how long the wind blows C. how large the body of water is D. how the waves are built up37. When the wave is blowing at 80 kilometers per hour, the height of most waves will be __________. A. about one meter B. about eight meters C. about eighty meters D. about ten meters38. Air rises when________. A. the wind is blowing B. the body of water is large C. there is powerful wave D. the sun heats the earth39. The best title for this selection is __________. A. What Causes Waves B. The Largest Waves in History C. Beautiful Waves D. Waves in the Pacific Ocean BAustralia, the last continent, was discovered by ships belonging to some European nations in the seventeenth century. These nations were less interesting in changing it into colony(殖民地) than in exploring it. As in the early history of the United States, it was the English who set up the settlements in Australia. This history and the geography of these two British colonies have some other things in mon as well.Australia and the United States are about the same in size, and their western lands are both not rich in soil. It was the eastern coast of Australia and America that the English first settled, and both colonies soon began to develop towards the west. However, this westward movement took place more because the English were searching for better land than because the population was increasing. Settlements of the western part of both countries developed quickly after gold was discovered in America in 1849, two years later in Australia.Although the development of these two countries has a lot in mon, there are some striking differences as well. The United States gained its independence from England by revolution while Australia won its independence without having to go to war. Australia, unlike the United States, was firstly turned into a colony by English prisoners and its economic development was in wheat growing and sheep raising. By 1922, for example, Australia had fifteen times more sheep than it had people, or almost half as many sheep as there are people today in the United States. Yet, in spite of these and other main differences, Australia and the United States have more in mon with each other than either one has with most of the rest of the world.40. Who turned Australia into a colony? A. Britain B. Several European countries C. The United States D. None of the above the early history of America and Australia, both colonies developed towards the west firstly for the reason that ________ ?A. the population was increasing rapidly in the eastB. the English thought there might be richer land t