what is the grammar difference between had/have?

Question

"It would have been a shame if you had to spend all your time inside the conference center"
The above sentence talks about the future, but why does it use "had to" if it is present.

Please help me!!!

Answer 1

b. Use of the past forms of the subjunctive
Like the past forms of the Subjunctive of the Active Voice, the past forms of the Subjunctive of the Passive Voice are used in wishes, and in statements containing false or improbable conditions.
e.g. I wish he were allowed to come.
It would have been better if they had been invited.

In the first example, the Simple Past Subjunctive of the Passive Voice, were allowed, is used in expressing a wish. In the second example, the Past Perfect Subjunctive of the Passive Voice, had been invited, is used in expressing the false condition they had been invited.

Answer 2

To make things even more confusing:
I think it should be either
"It would have been a shame if you HAD HAD to spend all your time inside the conference center" (talking about the past)
or
"It would BE a shame if you had to spend all your time inside the conference center" (talking about the present or future)

Concerning the grammatical terms, I have to correct what I said initially: "had" is a subjunctive here, expressing a possibility rather than an actual fact in the past.

Answer 3

Had is past tense. Have is present tense. The sentence you give as an example is incorrect grammar. More correctly: I would be a shame if you had to spend all your time inside the cc. OR It would have been a shame if you had spent all your time inside the cc.

Answer 4

Had is the past tense and have is the present tense of the word. As far as your example statement, I don't know why it uses the word like that. English is weird sometimes. I guess that's why I always hear that it's the hardest language to lean as a second language. Well, good luck. I hope you find the answer.