起重机吊着49000N的重物,当重物匀速上升时,钢丝绳拉物体的力____49000N;当重物匀速下降时,钢丝绳拉物体的力____49000N.(填“大于”、“等于”或“小于”)
如下图所示两幅图片反映的历史事件是中国解决历史遗留问题的成功范例.它践行了( )
A. Can I read the books here?
B. We usually talk quietly in the library
C. Keep your desk clean.
D. Take turns