直线的斜率为﹣2,在y轴上的截距是4,则直线方程为( )
A:2x+y﹣4=0
B:2x+y+4=0
C:2x﹣y+4=0
D:2x﹣y﹣4=0
补全短语:____the park
△ABC的边长AB=3,BC=5,AC=4,则AB→·BA→+AB→·BC→=( )
It is cold in the room. They ______ have turned off the heating.