A:司机看见红灯刹车
B:天热出汗
C:白细胞吞噬细菌
D:吃食物时,分泌唾液
50mm____49cm 9999____10000 7km____7000m
下列句子中划线的成语运用正确的一项是 ( )
My mother is a ____(退休) teacher, and she enjoys her life now.