2011-04-15 16:47:47

2011-04-15 16:46:25

2011-04-15 16:44:13

2011-04-15 16:42:00

2011-04-15 16:40:41

2011-04-15 16:37:09

3个月大时，婴儿听到的声音比我们成人要少15~30分贝，直到8~10岁，孩子的听力才能同成人完全一样

2011-04-15 16:34:00

2011-04-15 16:33:19

2011-04-15 16:33:00

2011-04-15 16:31:26