High-Q | 7 סימולציה

37

סימולציה מס' 7

פרק שלישי

– אנגלית

12. Several floors of the building collapsed in the explosion, causing debris to fly across the street and destroy the suspects' first-floor apartment.

(1) The debris from the suspects’ first-floor apartment, which was in a building where several floors collapsed, was destroyed in an explosion. (2) The explosion destroyed the suspects’ first-floor apartment, and debris that flung across the road caused several floors in the building to cave in. (3) The explosion flung debris into the building, which caused seven floors of the building to collapse and destroyed the suspect’s first-floor apartment. (4) The suspects’ first floor apartment was destroyed by debris, which was flung from across the street where an explosion caused several floors of a building to cave in.

Reading Comprehension This part consists of a reading passage followed by several related questions. For each question, choose the most appropriate answer based on the text .

Text I (Questions 13-17)

A pilot complained that the composite wing on a stealth fighter plane seemed too flexible. His fears were soon realized: it came off during flight, and the aircraft plummeted to the ground. Composites - which consist of high-strength carbon or glass fibers that are impregnated with a resin and then cured - are lighter than the more traditional aluminum, are more easily formed, and are often stronger. But compared with aluminum, which has 5 been used in aircraft since the early 20 th century, advanced composites are a recent technology, having been introduced in the 1970s. With relatively little experience with composites, how confident can engineers be about the lifespan and integrity of the material, which is being used more frequently in aircraft? Aeronautical engineer Chin-The Sun says that environmental factors such as ultraviolet light and moisture can change the materials’ 10 properties. “How long they will last, no one can tell you for sure.” However, material scientist Ken Reifsnider has developed a computer program designed to simulate the performance of composites, and thus predict their remaining strength and life. Among other tasks, the program analyzes a composite’s molecular chemistry and the chemical and thermal details of its manufacture and processing. This 15 information is then combined with studies of the composite while it is in motion, to yield estimates of the rate at which the composite changes over time. Thus far, Reifsnider says, the program predicts that composites will hold up better than most engineers expect. “These materials are more damage-resistant than traditional ones,” he says. “Aluminum and other metals eventually develop cracks, but cracks simply won’t grow in composites. Also, 20 composites can deteriorate considerably and still be safe, unlike aluminum and steel, which tend to deteriorate to a certain point and then fail completely.” So what about the crashed stealth fighter? The U.S. Air Force says it knows what caused its accident: mechanics failed to install 4 out of the 5 fasteners which hold the wing on. No matter how tough composites are, it appears they are no match for human error. 25

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