You use personally to emphasize that you are giving your own opinion.
Personally I think it's a waste of time.
在我看来,这是浪费时间。
You can disagree about them, and I personally do, but they are great ideas that have made people think.
你可以不同意它们,我个人就不同意,但是它们都是曾经启迪过人们的伟大思想。
If you do something personally, you do it yourself rather than letting someone else do it.
He is returning to Paris to answer the allegations personally.
他将回巴黎来亲自回应这些指控。
When the great man arrived, the club's manager personally escorted him upstairs.
当那位大人物到达时,俱乐部的经理亲自护送他上楼。
If you meet or know someone personally, you meet or know them in real life, rather than knowing about them or knowing their work.
He did not know them personally, but he was familiar with their reputation.
他并不认识他们,但久仰他们的大名。
You can use personally to say that something refers to an individual person rather than to other people.
He was personally responsible for all that people suffered under his rule.
他个人对在其统治下受苦难的人民负有全责。
You can use personally to show that you are talking about someone's private life rather than their professional or public life.
This has taken a great toll on me personally and professionally.
这给我的私人生活和事业造成了巨大的损失。
take something personally
If you take someone's remarks personally, you are upset because you think that they are criticizing you in particular.
I take everything too personally.
我过于把什么都看成是冲着自己而来的了。