The reason that his salary is low is that has just fulfilled his probation on 18th Oct.and will be regular employee then( after that).
（越正式越好） “他的收入比较低是因为他于10月18号刚满试用期,并转为正式雇员”.
The reason that his salary is low is that has just fulfilled his probation on 18th Oct.and will be regular employee then( after that).