Difference between 一直 and 总是
Are 一直 and 总是 essentially interchangeable? I understand that depending on the placement of 总是 you can emphasis different parts of a sentence, but semantically speaking, in terms of meaning, can I use these two words the same way?

For example:
我一直工作。
我总是工作。

Thanks!

Question

Difference between 一直 and 总是
Are 一直 and 总是 essentially interchangeable?  I understand that depending on the placement of 总是 you can emphasis different parts of a sentence, but semantically speaking, in terms of meaning, can I use these two words the same way?

For example:
我一直工作。
我总是工作。

Thanks!

Answer

Both 一直 and 總是 mean "always", but they are not interchangable.

一直 = tends to happen nonstop ; emphasizes a kind of stable/continuous state
總是 = emphasizes high probability or frequency (almost habitual)

Some examples I found online to highlight the differences: (Parentheses not explanations, rather comments)

這家飯店服務同到，我每次來北京總是喜歡住這兒 (you're not always there, but when you are, you always stay in the same place)

今天從早上到現在，一直在下雨。(It rained nonstop)

Answer

Your explanation is very clear; it is very helpful!  Thank you!

Answer

I'm not an expert or native speaker in chinese, but what I know is that
总是 means always (in the same way you use it in english)
一直 it's used when you want to express that an action is being done without any stop. 
I don't know if my explanation is clear.