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【简答题】
若 cos(α+β)=- 3 5 ， cos(α-β)= 12 13 ，则tanαtanβ=______．
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皮皮学刷刷变学霸
举一反三
【单选题】A recent survey shows the number of people who shop in stores ________， while far more are shopping online.
A.
decrease
B.
decreases
C.
is decreasing
D.
are decreasing
【单选题】A/An______is a person who is not present at a crime but who helps another in doing something criminal.
A.
assessor
B.
access
C.
acquaintance
D.
accessory
【简答题】______ will pay fifty pounds to anyone who helps the police to catch this man.
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