0 to 1 month     Eyes can feel the light within 1 feet approximately.     Sleeping time is quite long, only can use cry to express its emotion.     Response to the sound, easily get awakened by sudden sound .     2 to 3 months     Able to start to play and smile, the expression is more enrich.     Can distinguish the color and the shape gradually, whereby the sense of hearing also gradually keen.     Time of sleep and milk feeding is more orderly.     4 to 6 months     Able to distinguish the sound origin and the eyesight is getting better.     Starts to recognize people, will be shy while seeing the strangers.     Starts to laugh and mutter.