have yet to: If you have yet to do something, you have not done it
They have yet to make a decision.
I also read the tutorial on Yale and the post "Be yet to do" vs "have yet to do".
I guess I understand the meaning of it. I'd just like to know the difference between the example above and the one below
They are going to make a decision.
When should I use which?
You use are going to if there is a stated or known intention about a future action or event:
"They said they would vote on it today. They are going to make a decision."
It's essentially the same thing as this:
"They will make a decision."
You can use have yet to in the same situation—but it more accurately reflects a situation in the present:
"They said they would vote on it today—and we're still waiting. They have yet to make a decision."
There is an additional nuance that you are waiting for the thing to happen, rather than it being a simple statement about a future event.
In addition, you can also use have yet to in situations where there is no reasonable assumption about a future event:
"I have yet to win the lottery."
I might never win the lottery, but the use of have yet to is still an accurate description of the present.
(If I instead said, "I am going to win the lottery," as a statement of fact, I could be accused of rigging the event illegally—otherwise, how could I be certain of such a thing?)
Have yet to do means something like Have not done yet something you expect should have been done (keeping you waiting anxiously maybe). Are going to do is neutral and does not convey such expectation.
"We have yet to decide to go on vacation" means "We are still trying to decide whether to go on vacation but haven't yet decided.
On the other hand, "We are going to go on vacation." means "Our intention is to go on vacation though we have not done so yet." In both instances the vacation has not been realized. However, there is a more positive aspect to the 2nd sentence and the listener can infer that the vacation is imminent (It is going to happen.) In the 2nd sentence, the decision could go either way so the listener would be advised not to rely as much on the eventuality of a vacation. The decision makers could stall for a month, a week, etc. The word 'yet' puts the whole proposition into question.
