单选题
Before a new type of airplane goes into service, every part of it is tested again and again. But there are two tests that are more important than all the others. The first is called the "tank test". A modern airplane must fly very high in the sky. Air must be pumped into the plane so that the passengers can breathe. The metal structure(结构) of the plane has to be very strong for this reason. When the plane is filled with air, the air presses against the skin of the plane inside. The pressure (压力) on a small window is like a huge foot that is trying to get out. If a small part of the plane were to fail, the plane would explode in the sky. To test the structure of the plane, the plane is lowered into a huge tank or container of water. Then it is filled with air. The pressure inside the plane is greater than it ever will be when it is high up in the air. Finally, there is an explosion. This does not cause so much damage inside the water tank as it would anywhere else. Engineers can discover which part of the plane has broken. Then that part is made stronger. The most dangerous test happens when the new plane is going through test flights in the air. The test pilot must find out exactly what happens when the engines (发动机) are all shut off at once. The plane begins to fall like a stone. It is the pilot's job to find out how he can get control of the plane again. These two tests are examples of how planes are made safe before they ever carry passengers.
单选题
By doing the "tank test", the engineers can find out______. A. the amount of air in the plane B. the strength of the plane structure C. the pressure inside and outside the plane D. the power of the airplane engines
【正确答案】
B
【答案解析】[解析] 本文是一篇说明文，第一段即道出全文的主旨是要说明一种新型客机在投入使用之前所做的许多测试中的最重要的两项。第二段对其中一项测试tank test进行了说明。该段落的第2～4句说明了为什么飞机的结构要牢固。第5～7句从物理学上说明飞机在空中产生爆炸的原因。接下来才说明tank test测试的目的是To test the structure of the plane和测试方法。第二段末尾提到通过测试，Engineers can discover which part of the plane has broken. Then that part is made stronger.可以判断B选项涵盖了上述意思。
单选题
What will happen to the plane under the "tank test"? A. It will be broken. B. It will be made stronger. C. It will be filled with water. D. It wilt be tested by pilots.
【正确答案】
A
【答案解析】[解析] 第二段提到Then it is filled with air. The pressure inside the plane is greater than it ever will be when it is high up in the air. Finally，there is an explosion.即可判断，通过宽气加压使飞机爆炸来检测出飞机的薄弱部分，这是tank test的目的，因而A选项表明了tank test的结果，最合题意。B选项It will be made stronger是测试之后所要做的事。题干中的under the“tank test”是指在测试进行当中，因此不可选B。
单选题
According to the text, why are test flights most dangerous? A. The plane may explode in the air. B. The pilot may lose control of the plane. C. The engines may be damaged. D. Too much air may get into the plane.
【正确答案】
B
【答案解析】[解析] 本文的第三段对test flight“试飞”进行了说明。其中提到The test pilot must find out exactly what happens when the engines are all shut off at once. The plane begins to fall like a stone. It is the pilot's job to find out how he can get control of the plane again.即试飞员的任务是设法在发动机关闭的情况下重新控制飞机，但也就存在不能重新对飞机加以控制的可能。选项B中的lose control of意思是“失去对……的控制”，最贴近题意。
单选题
What might be the most suitable title for the text? A. Two Important Tests on Airplanes B. The Importance of Flying Safely C. The Danger of Testing Airplanes D. How Airplanes Are Made and Tested