A:have taken place
B:took place
C:have been taken place
D:are happening
下图为法国略图。7月,马赛正值高温多雨期。
已知O是锐角△ABC的外接圆圆心,∠A=60°,cosBsinC·AB→+cosCsinBAC→=2m·AO→,则m的值为( )