I came home very late last night,__________,early this morning. ( )
A:at the latest
B:in a word
C:on the whole
D:or rather
一辆汽车在高速公路上分别以v1、v2、v3的速度匀速直线行驶,且v1<v2<v3。其牵引力分别为F1、F2、F3,不考虑空气阻力,则( )