A:Why do you want to see the lions?
B:What do you want to do?
C:When do you want to go?
D:Why do you like the lion?
下面的图形是从上边物体的哪一面看到的?( ).
实验室用过量的稀盐酸和大理石制取CO2,取50g反应后的滤液,逐滴滴入碳酸钠溶液,测得滴入碳酸钠溶液的质量与产生沉淀质量的关系曲线如图所示.
回答下列问题:
若cosA=0.6753,则锐角A=____ (用度、分、秒表示).