agricultural base and bringing a new source of wealth to villagers. Para. 18, Passage A, Unit 1) Explanation: This noun is formed by adding the suffix -er to the already familiar verb observe. so we can find out the meaning of the word someone who observes Section b Green Spaces in Cities . Background Knowledge 1. Founded in 1972, the Trust for Public Land (TPL) is the only national nonprofit organization of America, working only to protect land for human enjoyment and health TPL helps protect land for recreation and soul food and to improve the health and quality of life of ameri 2. Portland, a seaport in the U.S.A., is the largest city of Maine 3. Maine is a state on the northeastern coast of U.S.A. Augusta is its capital. It 19s very hilly, with the White Mountain lying in the west. Maine was visited by Cabot in 1498 and colonized by the English in the 17th and 18th century 4. Portland Parks and Recreation Department is a city government department. Parks and Recreation Department can be found at all levels of governments in the U.s., whose mission is usually to assure access to leisure opportunities, enhancing natural beauty and 5. The Pacific Ocean is the largest ocean, separating America from Asia and Australia. Its length is 15,000km. Its width from Panama to Malaya is 19, 000km With its coasts it makes up a great volcanIc area. 6. Phoenix, the capital and largest city of Arizona, U.S.A., is the center of an irrigated agricultural district as well as electrical and electronic engineering, farm machinery, rcraft, food processing, metallurgy, and tourism 7. Arizona is a state in the Southeastern U.S.A. Its capital is Phoenix. It is divided by mountains with a high plateau in the northeast and desert in the southwest. The U.S.A acquired most of the state from Mexico in 1848, and the rest as part of the Gadsden Purchase in 1854. It became the 48th state of the U.S.A. in 1912 8. Salt River in this text refers to the Salt River lying in the middle east of Arizona Another is located in the middle north of Kentucky. Still there is another one in the northeast of missouri 9. Baltimore is a port and import-export center of Maryland, U.S.A., on an inlet from the Chesapeake(砌萨皮克,美国佛吉尼亚洲东南部城市)Bay 10. Lying at the base of the San Francisco Peaks at a height of 7,000 feet above sea level Flagstaff offers four distinctive seasons of weather, great hiking and outdoor recreation opportunities, a rich and diverse art and culture community. The quality of life in Flagstaff is so near perfect that each year it is judged one of the top cities in which to 11. The San Francisco Peaks is the mountain that lies at the north of flagstaff. Arizona. It is the highest place in Flagstaffagricultural base and bringing a new source of wealth to villagers. (Para. 18, Passage A, Unit 1) Explanation: This noun is formed by adding the suffix -er to the already familiar verb observe, so we can find out the meaning of the word: someone who observes. Section B Green Spaces in Cities I. Background Knowledge: 1. Founded in 1972, the Trust for Public Land (TPL) is the only national nonprofit organization of America, working only to protect land for human enjoyment and health. TPL helps protect land for recreation and soul food and to improve the health and quality of life of American communities. 2. Portland, a seaport in the U.S.A., is the largest city of Maine. 3. Maine is a state on the northeastern coast of U.S.A. Augusta is its capital. It i9s very hilly, with the White Mountain lying in the west. Maine was visited by Cabot in 1498, and colonized by the English in the 17 th and 18 th century. 4. Portland Parks and Recreation Department is a city government department. Parks and Recreation Department can be found at all levels of governments in the U.S., whose mission is usually to assure access to leisure opportunities, enhancing natural beauty and promoting tourism. 5. The Pacific Ocean is the largest ocean, separating America from Asia and Australia. Its length is 15,000km. Its width from Panama to Malaya is 19,000km With its coasts it makes up a great volcanic area. 6. Phoenix, the capital and largest city of Arizona, U.S.A., is the center of an irrigated agricultural district as well as electrical and electronic engineering, farm machinery, aircraft, food processing, metallurgy, and tourism. 7. Arizona is a state in the Southeastern U.S.A. Its capital is Phoenix. It is divided by mountains with a high plateau in the northeast and desert in the southwest. The U.S.A. acquired most of the state from Mexico in 1848, and the rest as part of the Gadsden Purchase in 1854. It became the 48 th state of the U.S.A. in 1912. 8. Salt River in this text refers to the Salt River lying in the middle east of Arizona. Another is located in the middle north of Kentucky. Still there is another one in the northeast of Missouri. 9. Baltimore is a port and import-export center of Maryland, U.S.A., on an inlet from the Chesapeake(砌萨皮克， 美国佛吉尼亚洲东南部城市) Bay. 10. Lying at the base of the San Francisco Peaks at a height of 7,000 feet above sea level, Flagstaff offers four distinctive seasons of weather, great hiking and outdoor recreation opportunities, a rich and diverse art and culture community. The quality of life in Flagstaff is so near perfect that each year it is judged one of the top cities in which to live. 11. The San Francisco Peaks is the mountain that lies at the north of Flagstaff, Arizona. It is the highest place in Flagstaff