— Nowadays people seem to be becoming more and more selfish.

— How much better life would be if we ______ to the values of the past!

A．would return

B．had returned

C．return

D．were to return

“静态值”的净空尺寸是指接触网不受（）的作用，或长期承受受电弓抬升力的作用，这两种情况下的净空尺寸。