The Harrier, informally referred to as the Harrier Jump Jet, is a fighter jet capable of
vertical/short takeoff and landing (VISTOL) operations. Originally developed by UK manufacturer Hawker Siddeley in the 1960s, the Harrier emerged as the only truly successful VISTOL design of the many    26    during that era. It was conceived to operate from improvised bases, such as car parks or forest clearings,    27    requiring large air bases. It combines the best aspects of a helicopter with those of a fighter jet.     28    , the world speed record for a helicopter is 249 mph while the Harrier can fly at 730 mph.
      Vertical takeoff and landing uses an enormous amount of skil    29    the pilot and also a large amount of fuel. To save fucl a simple ramp allows the plane to take off on a very short runway. The planes appear to hop    30    the air. Vents at the ends of tach wing can be used to direct some of the thrust and this allows the pilot to move the plane lett, tight, forwards and backwards while hovering.
【題組】26.
(A) committed
(B) scheduled
(C) instructed
(D) attempted