48. Hurricanes and tornadoes are not alike. __________ (1) A tornado's direction is unpredictable, but a hurricane's pathway is predictable. (2) A hurricane, on the other hand, may last for days or even weeks. (3) Also, the average time span for a tornado is one hour.(4) Finally, tornadoes occur in the central part of the United States and are accompanied by a violent whirling wind, while hurricanes occur in the tropics and have winds up to 100 miles an hour. (A) 3 1 2 4 (B) 2 1 3 4 (C) 2 3 1 4 (D) 1 3 2 4

49. Replacing a circuit breaker in a dark basement is one thing. __________ (1) It will perform many of the station's mundane tasks and reduce the number of death-defying spacewalks. (2) But what if you had to climb around the outside of a spacecraft orbiting hundreds of miles above the Earth to do it? (3) Fortunately, help is scheduled to arrive this month in the form of the Special Purpose Dexterous Manipulator, a versatile, \$200-million robotic handyman. (4) This kind of dangerous maintenance work has become fairly common for astronauts aboard the International Space Station, where they spend as much time fixing the \$100-billion-plus orbiting science lab as they spend performing actual research. (A) 2 4 3 1 (B) 4 1 2 3 (C) 3 2 1 4 (D) 2 3 1 4

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