I've always (no pun intended) wondered what the difference is between the two words. I thought they both meant always, but I've never quite grasped in what context they should be used.
Could anyone shed any light on this?
They are synonyms.
总是 places an emphasis on frequency.
一直 places an emphasis on consistency.
总是 means "every time."
一直 means "continuously."
The first is "discrete." The second is "continuous." But they both mean "always."