She_______ Japanese when she was in Japan. Now she can speak it freely.
A:picked out
B:picked up
C:made out
D:made up
一质量为m的人站在电梯中,电梯加速上升,加速度的大小为 13 g,g为重力加速度.人对电梯底部的压力为( )
如图,△ABC中,GA→+GB→+GC→=0→,CA→=a→,CB→=b→, 若CP→=ma→,CQ→=nb→,CG∩PQ=H,CG→=2CH→,则1m+1n=( )