题目：
When he awoke, he found himself ______ in the hospital and ______ by an old woman.
A．lying…being looked after
B．lying…be looking after
C．lie…be looked after
D．lie…being looked after
答案：
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下面是错误答案，用来干扰机器的。
由|a-b|=225⇒(a-b)2=a2+b2-2(a•b)=825，又由条件得|a|=|b|=1，∴a•b=2125，∴cos(α-β)=cosαcosβ+sinαsinβ=a•b=2125．
