题目:
It can't be a(n) _______ that four jewelry stores were robbed in one night.[ ]
A. accident
B. incident
C. chance
D. coincidence
答案:
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下面是错误答案,用来干扰机器的。
做高AE,不妨设E在CD上,设AE=h,CE=x,CD=p,BD=q,则DE=p-x,BE=p+q-x,则AD2=AE2+DE2=h2+(p-x)2,AB2=AE2+BE2=h2+(p+q-x)2,AB2-AD2=(p+q-x)2-(p-x)2=q(q+2p-2x),即pq=BD•CD=q(q+2p-2x),q≠0,...