雅思阅读提高方法

　　推理判断是指根据阅读材料中的内容推断出题目要填写的内容或要选择的选项。大多数的推理判断只需要一般推理即可判断出答案，少数题目需要经过比较复杂的推理才能判断出答案。

E AIR TRAFFIC CONTROL IN THE USA To meet this challenge, the following elements were put into effect. First, ATC extends over virtually the entire United States. In general, from 365m above the ground and higher, the entire country is blanketed by controlled airspace. In certain areas, mainlynear airports, controlled airspace extends down to 215m above the ground, and,in the immediate vicinity of an airport, all the way down to the surface. Controlledairspace is that airspace in which FAA regulations apply. Elsewhere, in uncontrolledairspace, pilots are bound by fewer regulations. In this way, the recreational pilot whosimply wishes to go flying for a while without all the restrictions imposed by the FAAhas only to stay in uncontrolled airspace, below 365m, while the pilot who does wantthe protection afforded by ATC can easily enter the controlled airspace.

F The FAA then recognised two types of operating environments. In good meteo-rological conditions, flying would be permitted under Visual Flight Rules (VFR) ,which suggests a strong reliance on visual cues to maintain an acceptable level ofsafety. Poor visibility necessitated a set of Instrumental Flight Rules (IFR), under whichthe pilot relied on altitude and navigational information provided by the plane'sinstrument panel to fly safely. On a clear day, a pilot in controlled airspace canchoose a VFR or IFR flight plan, and the FAA regulations were devised in a way whichaccommodates both VFR and IFR operations in the same airspace. However, a pilotcan only choose to fly IFR if they possess an instrument rating which is above andbeyond the basic pilot's license that must also be held.

G Controlled airspace is divided into several different types, designated by letters of thealphabet. Uncontrolled airspace is designated Class F, while controlled airspace below5,490m above sea level and not in the vicinity of an airport is Class E. All airspace above5,490m is designated Class A. The reason for the division of Class E and Class A airspacestems from the type of planes operating in them. Generally, Class E airspace is whereone finds general aviation aircraft (few of which can climb above 5,490m anyway), andcommercial turboprop aircraft. Above 5,490m is the realm of the heavy jets, since jet engines operate more efficiently at higher altitudes. The difference between Class E andA airspace is that in Class A, all operations are IFR, and pilots must be instrument-rated,that is, skilled and licensed in aircraft instrumentation. This is because ATC controlof the entire space is essential. Three other types of airspace, Classes D,C and B,govern the vicinity of airports. These correspond roughly to small municipal, medium-sized metropolitan and major metropolitan airports respectively, and encompass anincreasingly rigorous set of regulations. For example, all a VFR pilot has to do to enterClass C airspace is establish two-way radio contact with ATC. No explicit permissionfrom ATC to enter is needed, although the pilot must continue to obey all regulationsgoverning VFR flight. To enter Class B airspace, such as on approach to a majormetropolitan airport, an explicit ATC clearance is required. The private pilot whocruises without permission into this airspace risks losing their license.