1.we learn a lot about keeping ourselves safe fr

1.we learn a lot about keeping ourselves safe fr
om fires,floods earthpuakes and traffic accidents .请问keeping ourselves safe from 短语keep sb +adi+ from是固定搭配吗,另 learn about 和learn from有什么区别
2.just as i was leaving the house ,the phone rang.请问leave 是非延续性动词呀,能加ing吗?是不是用正在进行时表达将来时态的移动动词
3.yesterday evening ,i was walking along the street when i suddenly met my maths teacher.请问这个句子两种译法都对吗:昨天晚上当我突然遇见我的数学老师的时候,我正沿着这条街散步.昨天晚上当我正在散步的时候我突然遇见了我的数学老师.