在工作之余，我坚持学习专业知识的翻译：In his spare time, I keep learning expertise 什么意思？中文翻译英文，英文翻译中文，怎么说？

青云英语翻译

In his spare time, I insisted to learn professional knowledge

In his spare time, I keep learning expertise

In after-working hours, I persisted studies the specialized knowledge

In his spare time and I insist on learning expertise

In his spare time, I keep learning expertise