为更专门的工作 for more specialized work
为晋升的前途 for prospects of promotion
为更高层次的工作责任 for higher responsibility
为扩大工作经验 for wider experience
找一份更好的工作 to seek a better job
由于雇用期满 due to expiry of employment
找到了更好的工作 sought a better job
由于公司倒闭 due to close-down of company