The Harrier, informally referred to as the Harrier Jump Jet, is a fighter jet capable ofvertical/short takeoff and landing (VISTOL) operations. Originally developed by UKmanufacturer Hawker Siddeley in the 1960s, the Harrier emerged as the only truly successfulVISTOL design of the many __26__ during that era. It was conceived to operatc fromimprovised bases, such as car parks or forest clearings, __27__ requiring large air bases. Itcombines the best aspects of a helicopter with those of a fighter jet. __28__, the world speedrecord for a helicopter is 249 mph while the Harrier can fly at 730 mph.
 Vertical takeoff and landing uscs an enormous amount of skill__29__ the pilot and also alarge amount of fuel. To save fuel a simple ramp allows the plane to take off on a very shortrunway. The planes appear to hop _ 30 _ the air. Vents at the ends of each wing can be used todirect some of the thrust and this allows the pilot to move the plane left, right, forwards andbackwards while hovering.
【題組】26.
(A) committed
(B) scheduled
(C) instructed
(D) attempted