3. What is NOT true about the scramjet engine?

　　A It goes slower than a rocket.

　　B It extracts oxygen from the air that flows through the engine.

　　C It works only at speeds greater than five times the speed of sound.

　　D It doesn’t carry its own oxygen supply.

　　4. What did Werner J.A.Dahm of the University of Michigan say about the Hyper-X test flight?

　　A It indicated the birth of a very fast airplane.

　　B It was self-powered，so it lasted only 11 seconds.

　　C It can transportcargo quickly and cheaply to the brink of space.

　　D It is a major milestone in the journey of making a new type of very fast airplanes，

　　5. What has NASA planned to do?

　　A To make another 11-second hypersonic flight at 10 times the speed of the sound.

　　B To make three more Hyper-X experiments.

　　C To retest the aircraft that is left.

　　D To make the aircraft fly higher and longer.

　　答案與題解：

　　1. C Hyper-X之所以打破紀錄是因為它的飛行速度是音速的7倍。它不是第一架空氣噴氣式飛機，也不是第一架超音速飛機，所以A和D都不對。Hyper-X的試飛并未繞赤道飛行，所以B也是錯誤的選擇。

　　2. B 第四段講了三種發動機的氧氣：噴氣式發動機是從空氣中汲取氧氣，火箭發動機必須自攜氧氣，而超音速沖壓噴氣發動機則不必白攜氧氣，而這正是Hyper-X使用的發動機裝置。

　　3. A 根據第五段內容，B、C、D都是正確的說法。第四段最后一句告訴我們，A的說法是不正確的。

　　4. D 文章的第六段中，密歇根大學的研究人員Werner J.A.Dahm說，Hyper-X的試飛成功只是研制一種新式快速飛機過程中的一個里程碑(a major milestone on the way to a new breed of very fast airplanes)，而不是新型飛機的誕生。所以，D是正確選擇，A是錯誤選擇。B也不是Werner J.A.Dahm想要表達的意思。C是其他下程師而不是Werner J.A.Dahm說的話。

　　5. A 答案可在最后一段找到。