Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 19 to 23.
Any change in one part of an ecosystem can cause changes in other parts. Droughts, storms and fires can change ecosystems. Some changes (19)................ecosystems. If there is too little rainfall, plants will not have enough water to live. If a kind of plant dies off, the animals (20)................feed on it may also die or move away. Some changes are good for ecosystems. Some pine forests need fires for the pine trees to reproduce. The seeds are sealed inside pinecones. Heat from a forest fire melts the seal and lets the seeds (21)................. Polluting the air, soil, and water can harm ecosystems. Building (22)................on rivers for electric power and irrigation can harm ecosystems around the rivers. Bulldozing wetlands and cutting down forests destroy ecosystems. Ecologists are working with companies and governments to find better ways of (23)................fish, cutting down trees, and building reservoirs. They are looking for ways to get food, lumber, and other products for people without causing harm to ecosystems.
(22)
A.moats
B.dams
C.ditches
D.bridges

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Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions from 41 to 45.
Chu Van An High School is one of the oldest and most prestigious state schools in Viet Nam. Established in 1908 by the French, the school was located beside the West Lake, and was originally named after the location it was in. It is a very pleasant, spacious school with great views of the lake from the classroom windows. In 1943, the school was moved to Ninh Binh, and was not moved back to Ha Noi until 1945. In that year, the school was renamed Chu Van An after a famous Vietnamese Confucianism teacher of the Tran Dynasty. Professor Nguyen Gia Tuong became the first Vietnamese principal of the school. Many famous people like ex-Prime Minister Pham Van Dong, Doctor Ton That Tung and poet Xuan Dieu used to be the school's students.
Today the school is still located in the same area, and has maintained its prestige, as well as its reputation as one of the top schools in Ha Noi. It is very difficult to be admitted to the school. Every year, there are around three thousand applicants but only about five hundred are admitted. Those applicants have to take an entrance examination conducted by the Department of Education and Training of Ha Noi.
All of the following are true about the school EXCEPT____________.
A.the school is large
B.the school was originally named after the location it is in
C.the school admits three thousand students every year
D.the school has a view of the West Lake