读一读，判断句子表述是(√)否(×)正确。

( ) 1. The traffic lights have three colours.

( ) 2. Red is stop and yellow is go.

( ) 3. When (当……时) the traffic light is blue, you can go.

发掘教材的教育因素，就是找出教材中有关思想品德教育的因素。