___      three times in a row, the boxer decided to make a fourth attempt, though．

A．Having defeated

B．To have defeated

C．Having been defeated

D．To defeat

在圆筒的不同高度处开三个小孔，当筒里灌满水时，各个小孔喷出水的情况如图5所示。这表明水对容器的           有压强，而且压强随           的增加而增大。