737-300与 737-200具有相同的基本设计，机体伸长了 104英寸，翼尖延伸了 14英寸，水平尾翼延伸了 36英寸，还多了个大的脊鳍和增强的水平尾翼。

(8) The 737-400, relative to the 737-300, has body stretch of 120 inches, tow

additional overwing exit, tail skid, and strengthened landing gear.
737-400与 737-300相比较，机身伸长了 120英寸，多了两个逃生出口，尾部滑轨及加强了起落架。
(9) The 737-500 uses the 737-300 basic structure with a 94 inches shorter body and a revised forward and aft fairing (wing to body).
737-500使用了 737-300的基本结构，机身短了 94英寸，并且修改了前后整流罩（机翼到机体）。
LESSON 2 THE PNEUMATICS SYSYTEM增压系统
一、生词
目的  Purpose 压缩空气  compressure Air 压缩空气  pneumatic
环境  Environment 阶段，相位  Phase 得到  Obtain
发动机引气  Engine bleed 外部的  External 车  Cart
接头  Connector 整流罩  Cowl 热的  Thermal
防冰  Anti-icing 也，此外  Also 提供  provide
饮用水  Potable water 液压的  Hydraulic 启动器  Starter
在 …之内  Within 正常的  Normal 取代  Substitute
满足  Meet 需要，要求  Need 上部、顶部  Top
图形  Figure 绝缘  Isolation 活门  Valve
管道  Duct 结合、连接  Join 交叉、跨接  crossover
管理、调整  govern 适当的  appropriate

二、TEXT
(1) the purpose of the pneumatic sysytem is to supply compressed air for a controlled temperature and pressure environment during all phases of flight and ground operation .air is obtained from engine bleeds. APU、or from an extermal ground cart through a connector located on the fuselage.

增压系统的作用是为飞行及地面所有阶段的温度和压力控制提供压缩空气。压缩空气的来源可以是发动机引气、 APU、或通过机身上的连接头与地面气源车相连供气。

(2) The pneumatic system controls the temperature and the pressure of engine bleed air source. The pneumatic system provides high temperature, high

pressure air for the air conditioning .pressurization, wing and cowl thermal anti-icing .also, the pneumatic system provides pressure for the potable water system, hydraulic system and engine starters. The engine bleed air systems are located on the engine and within the support strut.
增压引气控制发动机引气的温度和压力。增压系统为空调、增压系统、机翼及整流罩热防冰系统提供高温、高压引气。同时，增压系统还给饮用水系统、液压系统和发动机起动系统提供压力。发动机引气系统位于支架内部发动机上。
(3) The normal cabin air source is obtained from the 5th-stage of the engines at low –engine power, 9th-stage air automatically substitutes to meet user system needs.

正常情况下，客舱空气来自于发动机低能量的第 5级， 9级空气自动分配以满足用户系统的需要。

(4) On the top of figure 2-1, the isolation valve separates the left and right halves of the system. On the left side of the isolation valve, the APU bleed air duct joins the left side crossover duct; on the right side ,the pneumatic ground service connector joins the right side crossover duct. From these ducts the user system are supplied with pressurized air ,governed by the appropriate control valves.