Current/ Present/ Existing/ ..... how to use them in context?

[SOON]

I have a little confusion in using such words: Current - Present - Existing in certain contexts. Pls kindly make me clearer. Tks a bunch!

[jlinger]

Try some examples and we can try to point out the differences in meaning - if any. They are usually identical.

[SOON]

For example:
My current/ present job is an civil construction engineer.
The present construction site is in mess.
The existing soil quality is good enough for our construction.

Someone tells me that "current" is referred to something specific (like material), and "present" to sth like spirit...Very confused...