英语语法分析

Replaced L main wheel in postflight, check OK.

航后更换左主轮，检查正常。

Postflight check found L AFT NAV light not on.

航后检查发现左后航行灯不亮。

Postflight check found L main gear exposed threads due wearing.

航后检查发现左主轮磨损见线。