— That's a good habit.
A:keep
B:keeps
C:to keep
句型转换
已知向量a→=3,1,b→=x,-2,c→=0,2,若a→⊥b→-c→,则实数x的值为( )
如图所示,△ABC中,∠C=90°,AB的垂直平分线交BC于点D,连接AD,若∠CAD=20°,则∠B=( )