During her internship, she was very motivated and humble. In fact, she was always willing to learn from her co-workers/colleagues. Note: 1. We don't add "period" to the end of "during her internship". 2. I think you mean "humble" instead of "modest". Also, "modest" is an adjective and not an adverb. You would need to use "modestly" with "to behave". Anyhow, if you are humble at work, it means that you learn from others and aren't a snob who thinks they know everything. 3. I think you mean "very motivated" instead of "highly activated". 4. In American English, we tend to say "co-workers" instead of "colleagues" in an office setting.

其实我个人觉得，“period"可以去掉

在实习期间，她表现的既谦卑，也表现的十分活跃，总是十分乐意向周围同事学习。