—What does "___________" mean?

—That means, the things that people do mean more than what they say.

A．Easier said than done

B．Actions speak louder than words

C．Honesty is the best policy

D．Constant dropping wears the stone

在“探究凸透镜成像特点”的实验中，首先应记录凸透镜的______，然后依次将蜡烛、凸透镜和光屏放在______上，并将烛焰的中心、凸透镜和光屏中心调到______．实验中所需要测量和记录的物理量是______．