A:in; in
B:since; since
C:in; since
D:since; in
- What's _____ matter with you?
- I have _____ toothache.
如图所示,并排放在光滑水平面上的两物体的质量分别为m1和m2,且m1=2m2。在用水平推力F向右推m1时,两物体间的相互压力的大小为N,则( )