Where was the passage most probably excerpted（）

A．cross to the opposite side of the road before signaling the bus or tram to stop
B．step into the road in good time before the bus or tram arrives.
C．not leave the pavement until the bus or tram has stopped.
D．only leave the pavement to signal the bus or tram to stop.

A．They get rid of intuition,
B．They make it more logical.
C．They reduce everything to numbers.
D．They give an idea of the amount of error involved.