783.Mark _______ have hurried.After driving at top speed,he arrived half an hour early.
A.needn't
B.wouldn't
C.mustn't
D.couldn't
784.“You _______ have a wrong number,”she said.“There's no one of that name here.”
A.need
B.can
C.must
D.would
783.答案是A;根据后面的语境，提前半个小时到达，说明Mark本来不必那么匆忙，所以用needn't have done sth.的结构。
784.答案是C;根据句意得知，前一个句子表示肯定推测，故用must。
