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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 questions The mineral particles found in soil range in size from microscopic clay particles to large boulders. The most abundant particles - sand, silt, and clay - are the focus of examination in studies of soil texture. Texture is the term used to describe the line composite sizes of particles in a soil sample, typically several representative handfuls . To measure soil texture, the sand, silt, and clay particles are sorted out by size and weight. The weights of each size are then expressed as a percentage of the sample weight. In the field, soil texture can be estimated by extracting a handful of sod and squeezing the damp soil into three basic shapes; (1) cast, a lump formed by squeezing a sample in a clenched fist; (2) thread, a pencil shape formed by rolling soil between the palms; and (3) ribbon, a flatfish shape formed by squeezing a small sample between the thumb and index finger. The behavioral characteristics of the soil when molded into each of these shapes, if they can be formed at all, provides the basis for a general textural classification. The behavior of the soil in the hand test is determined by the amount of clay in the sample. Clay particles are highly cohesive, and when dampened , behave as a plastic. Therefore the higher the clay content in a sample, the more refined and durable the shapes into which it can be molded. Another method of determining soil texture involves the use of devices called sediment sieves, screens built with a specified mesh size. When the soil is filtered through a group of sieves, each with a different mesh size, the particles become grouped in corresponding size categories. Each category can be weighed to make a textural determination. Although sieves work well for silt, sand, and larger particles, they are not appropriate for clay particles. Clay is far too small to sieve accurately; therefore, in soils with a high proportion of clay, the fine particles are measured on the basis of their settling velocity when suspended in water. Since clays settle so slowly, they are easily segregated from sand and silt. The water can be drawn off and evaporated, leaving a residue of clay, which can be weighed.  The author mentions "several representative handfuls" in the passage in order to show ______.

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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 questions Mandatory volunteering made many members of Maryland's high school class of 97 grumble with indignation. They didn't like a new requirement that made them take part in the school's community service program. Future seniors, however, probably won't be as resistant now that the program has broken in. Some, like John Maloney, already have completed their required hours of approved community service. The Bowie High School sophomore earned his hours in eighth grade by volunteering two nights a week at the Larkin- Chase Nursing and Restorative Center in Bowie.He played shuffle board, cards, and other games with the senior citizens. He also helped plan parties for them and visited their rooms to keep them company. John, fifteen, is not finished volunteering. Once a week he videotapes animals at the Prince George's County animal shelter in Forestville. His footage is shown on the Bowie public access television channel in hopes of finding homes for the animals. "Volunteering is better than just sitting around," says John, "and I like animals; I don't want to see them put to sleep." He's not the only volunteer in his family. His sister, Melissa, an eighth grader, has completed her hours also volunteering at Larkin-Chase. "It is a good idea to have kids go out into the community, but it's frustrating to have to write essays about the works," she said. It makes you feel like you're doing it for the requirement and not for yourself." The high school's service learning office, run by Beth Ansley, provides information on organizations seeking volunteers so that students will have an easier time fulfilling their hours. "It's ridiculous that people are opposing the requirements," said Amy Rouse, who this summer has worked at the Ronald McDonald House and has helped to rebuild a church in Clinton. "So many people won't do the service unless it's mandatory," Rouse said, "but once they start doing it, they'll really like it and hopefully it will become a part of their lives - like it has become a part of mine."  The best title of the passage could be ______.

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Đọc thầm và trả lời câu hỏi. Kể về người anh hùng dân tộc Ngô Quyền Ngô Quyền (899 - 944) quê ở Đường Lâm, Sơn Tây. Ông có sức khoẻ phi thường, chí lớn, mưu cao, mẹo giỏi. Ông là con rể Tiết độ sứ Dương Đình Nghệ. Ngô Quyền đem ba nghìn quân từ Ái Châu kéo thẳng ra thành Đại La giết chết tên phản nghịch Kiều Công Tiễn, trừ hậu hoạ cho dân tộc. Vua Nam Hán sai con là Hoằng Thao đem mấy nghìn chiếc thuyền sang xâm lược nước ta. Ngô Quyền kéo đại binh ra cửa sông Bạch Đằng để nghênh chiến. Ông sai quân sĩ lấy gỗ đẽo nhọn, bịt sắt cắm xuống lòng sông kéo dài hàng chục dặm. Khi quân Nam Hán tiến vào, Ngô Quyền sai tướng sĩ đem thuyền nhẹ ra khiêu chiến, rồi giả vờ thua chạy, lừa cho chiến thuyền giặc vượt qua bãi cọc ngầm. Nước thuỷ triều bắt đầu rút, Ngô Quyền đổ quân mai phục ra vây đánh. Giặc Nam Hán thua to, quay chiến thuyền chạy ra biển. Chiến thuyền giặc bị cọc nhọn đâm vỡ tan tành. Hoằng Thao bị giết chết cùng hàng vạn giặc. Dòng sông Bạch Đằng đỏ ngầu máu giặc Nam Hán. Đó là vào cuối năm 938. Chiến thắng Bạch Đằng thể hiện sức mạnh và ý chí chống xâm lăng, tài nghệ quân sự tuyệt vời của tổ tiên ông cha ta. Thù trong giặc ngoài đã dẹp tan, Ngô Quyền lên làm vua, đóng đô ở cổ Loa, mở ra kỉ nguyên độc lập cho nước ta sau một nghìn năm bị phương Bắc thống trị. Dựa vào nội dung bài đọc trên, khoanh tròn vào chữ cái đặt trước câu trả lời đúng nhất hoặc làm theo yêu cầu của mỗi câu hỏi. Tác giả giới thiệu Ngô Quyền là người như thế nào?

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Tập làm văn: Em hãy điền những điều cần thiết vào tờ giấy dưới đây:                      PH. 19a                                     CỘNG HOÀ XÃ HỘI CHỦ NGHĨA VIỆT NAM TỔNG CÔNG TI BCVT VIỆT NAM                        Độc lập – Tự do – Hạnh phúc   Giấy đặt mua báo chí trong nước                                                                                                Số........... Tên độc giả: ..... Địa chỉ: Đặt mua các loại báo chí dưới đây:  TÊN BÁO CHÍ Thời hạn Số lượng 1 kỳ Giá tiền 1 tháng (3 tháng) Thành tiền Từ tháng Đến tháng ………….. ……….. ………….. ………….. ………….. ………….. ………….. ……….. ………….. ………….. ………….. ………….. ………….. ……….. ………….. ………….. ………….. ………….. ………….. ……….. ………….. ………….. ………….. …………..         Cộng:   Thành tiền viết bằng chữ: Năm trăm hai mươi hai nghìn đồng chẵn. Nhận đặt mua bì số......../Q             Kế toán trưởng                     Ngày....tháng.....năm...               Kí tên                                         Kí tên                                     Thủ trưởng                                                                                                             Đơn vị đặt mua  

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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 questions Most languages have several levels of vocabulary that may be used by the same speakers. In English, at least three have been identified and described. Standard usage includes those words and expressions understood, used, and accepted by a majority of the speakers of a language in any situation regardless of the levels of formality. As such, these words and expressions are well defined and listed in standard dictionaries. Colloquialisms, on the other hand, are familiar words and idioms that are understood by almost all speakers of a language and used in informal speech or writing, but not considered acceptable for more formal situations. Almost all idiomatic expressions are colloquial language. Slang, however, refers to words and expressions understood by a large number of speakers but not accepted as appropriate formal usage by the majority. Colloquial expressions and even slang may be found in standard dictionaries but will be so identified. Both Colloquial usage and slang are more common in speech than in writing. Colloquial speech often passes into standard speech. Some slang also passes into standard speech, but other slang expressions enjoy momentary popularity followed by obscurity. In some cases, the majority never accepts certain slang phrases but nevertheless retains them in their collective memories. Every generation seems to require its own set of words to describe familiar objects and events. It has been pointed out by a number of linguists that three cultural conditions are necessary for the creation of a large body of slang expressions. First, the introduction and acceptance of new objects and situations in the society; second, a diverse population with a large number of subgroups; third, association among the subgroups and the majority population. Finally, it is worth noting that the terms "standard", "colloquial" and "slang" exist only as abstract labels for scholars who study language. Only a tiny number of the speakers of any language will be aware that they are using colloquial or slang expressions. Most speakers of English will, during appropriate situations, select and use all three types of expressions.  Which of the following is the main topic of the passage?

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