Example : I have yet to see the results.
Details are yet to be worked out.

Example : So far he hasn't called.
The sun isn't up yet.

Synonyms : as yet, heretofore, hitherto, so far, thus far, til now, until now, up to now

Example : Looked sick and felt even worse.
An even (or still) more interesting problem.
Still another problem must be solved.
A yet sadder tale.

Synonyms : even, still

Example : He longed for the flowers that were yet to show themselves.
Sooner or later you will have to face the facts.
In time they came to accept the harsh reality.

Synonyms : in time

Example : This is the best so far.
The largest drug bust yet.

Synonyms : so far

Example : Although I'm a little afraid, however I'd like to try it.
While we disliked each other, nevertheless we agreed.
He was a stern yet fair master.
Granted that it is dangerous, all the same I still want to go.

Synonyms : all the same, at the same time, even so, however, nevertheless, nonetheless, notwithstanding, still, withal