阅读理解 Three years after its first test flight ended in an explosion, NASA on March 27 successfully launched an experimental jet that the agency believes it (47)______ a record-setting speed of about 5,000 mph. The unpiloted X43A made an 11 second rocket boosted flight, then went through some twists and (48)______ during a six-minute glide before (49)______ into the Pacific Ocean about 400 miles off the California (50)______ . Flight engineer Lawrence Huebner said preliminary data (51)______ the needle-nosed jet reached a maximum speed of slightly over seven times the speed of sound, or about 5,000 mph, after a rocket boosted it to about 3,500 mph. Huebner said it was the first time an "air breathing" jet had ever traveled so fast. The rocket powered X15 reached Mach 6.7 in 1967. NASA built the X43A under a $250 million program to develop and test an (52)______ type of engine called a supersonic combustion ramjet, or scramjet. In theory, the air breathing engine could (53)______ an airplane to speeds of Mach 7 or faster, (54)______ around-the-world flights that would (55)______ several hours. The Department of Defense also is working on the technology, which is (56)______ for use in bombers that quickly could reach targets anywhere on the globe. A third X43A could fly as early as the fall. Word Bank A) turns I) border B) plunging J) foreign C) complicate K) take D) reached L) propel K) coast M) eyeing F) enabling N) indicated G) spend O) haughty H) exotic