A:
B:
C:
D:
在“探究影响浮力大小的因素”实验中,物体A静止时,弹簧测力计示数分别如图所示,试回答下列问题:
How many people died in the Bund tragedy in Shanghai on Dec. 31, 2014?
指南针传到欧洲是由( )