According to the passage, approximately how many non-native users of English are there in the world today?

For many people who live in cities, parks are an important part of the landscape. They provide a place for people to relax and play sports, as well as a refuge from the often harsh environment of a city. What people often overlook is that parks also provide considerable environmental benefits. One benefit of parks is that plants absorb carbon dioxide—a key pollutant—and emit oxygen, which humans need to breathe. According to one study, an acre of trees can absorb the same amount of carbon dioxide that a typical car emits in 11,000 miles of driving. Parks also make cities cooler. Scientists have long noted what is called the Urban Heat Island Effect: building materials such as metal, concrete, and asphalt absorb much more of the sun’s heat and release it much more quickly than organic surfaces like trees and grass. Because city landscapes contain so much of these building materials, cities are usually warmer than surrounding rural areas. Parks and other green spaces help to mitigate the Urban Heat Island Effect. Unfortunately, many cities cannot easily create more parks because most land is already being used for buildings, roads, parking lots, and other essential parts of the urban environment. However, cities could benefit from many of the positive effects of parks by encouraging citizens to create another type of green space: rooftop gardens. While most people would not think of starting a garden on their roof, human beings have been planting gardens on rooftops for thousands of years. Some rooftop gardens are very complex and require complicated engineering, but others are simple container gardens that anyone can create with the investment of a few hundred dollars and a few hours of work. Rooftop gardens provide many of the same benefits as other urban park and garden spaces, but without taking up the much-needed land. Like parks, rooftop gardens help to replace carbon dioxide in the air with nourishing oxygen. They also help to lessen the Urban Heat Island Effect, which can save people money. In the summer, rooftop gardens prevent buildings from absorbing heat from the sun, which can significantly reduce cooling bills. In the winter, gardens help hold in the heat that materials like brick and concrete radiate so quickly, leading to savings on heating bills. Rooftop vegetable and herb gardens can also provide fresh food for city dwellers, saving them money and making their diets healthier. Rooftop gardens are not only something everyone can enjoy, they are also a smart environmental investment.

According to the author, one advantage that rooftop gardens have over parks is that they ................

The author’s tone in the passage is best described as .........

The word "representative" in the last paragraph is closest in meaning to ...............

What does the author mean by staring that, "At interpersonal levels, tone may reflect ideas and feelings over and above the words chosen" in lines 8- 9?

The word "scrutinized" in the fourth paragraph could be replaced by .............

Rachel Carson was born in 1907 in Springsdale, Pennsylvania. She studied biology at college and zoology at Johns Hopkins University, where she received her master’s degree in 1933. In 1936, she was hired by the U.S. Fish and Wildlife Service, where she worked most of her life. Carson’s first book, Under the Sea Wind, was published in 1941. It received excellent reviews, but sales were poor until it was reissued in 1952. In that year she published The Sea Around Us, which provided a fascinating look beneath the ocean’s surface, emphasizing human history as well as geology and marine biology. Her imagery and language had a poetic quality. Carson consulted no less than 1,000 printed sources. She had voluminous correspondence and frequent discussions with experts in the field. However, she always realized the limitations of her nontechnical readers. In 1962, Carson published Silent Spring, a book that sparked considerable controversy. It proved how much harm was done by the uncontrolled, reckless use of insecticides. She detailed how they poison the food supply of animals, kill birds and fish, and contaminate human food. At the time, spokesmen for the chemical industry mounted personal attacks against Carson and issued propaganda to indicate that her findings were flawed. However, her work was proved by a 1963 report of the President’s Science Advisory Committee. (Source: TOEFL Reading) Read the text carefully and do the task The passage mainly discusses Rachel Carson’s work ............Rachel Carson was born in 1907 in Springsdale, Pennsylvania. She studied biology at college and zoology at Johns Hopkins University, where she received her master’s degree in 1933. In 1936, she was hired by the U.S. Fish and Wildlife Service, where she worked most of her life. Carson’s first book, Under the Sea Wind, was published in 1941. It received excellent reviews, but sales were poor until it was reissued in 1952. In that year she published The Sea Around Us, which provided a fascinating look beneath the ocean’s surface, emphasizing human history as well as geology and marine biology. Her imagery and language had a poetic quality. Carson consulted no less than 1,000 printed sources. She had voluminous correspondence and frequent discussions with experts in the field. However, she always realized the limitations of her nontechnical readers. In 1962, Carson published Silent Spring, a book that sparked considerable controversy. It proved how much harm was done by the uncontrolled, reckless use of insecticides. She detailed how they poison the food supply of animals, kill birds and fish, and contaminate human food. At the time, spokesmen for the chemical industry mounted personal attacks against Carson and issued propaganda to indicate that her findings were flawed. However, her work was proved by a 1963 report of the President’s Science Advisory Committee. (Source: TOEFL Reading) 

The passage mainly discusses Rachel Carson’s work ............

What does the passage mainly discuss?