14．Only after the second tower of the World Trade Centre ________ did people know it was not an accident，but an attack of some kind.
A．had hit B．did fall C．was hit D．was fallen
答案 C [“only＋ 状语”置于句首，句子用倒装语序。]
15．Remember this: A chance ________ a prepared mind.Whenever it appears，don't let it go.
A．excites B．foresees C．favours D．abuses
答案 C [favour意为“偏爱”。句意：机会偏爱有准备的人。]
