Q: I have a question about the subjunctive. In the sentence “I would like to live in a house that has/had five rooms,” which is the correct form of the verb “have”?
A: The subjunctive isn’t being used here. I think you’re confusing the conditional tense with the subjunctive mood.
The correct sentence is “I would like to live in a house that has five rooms.” The first verb (“like”) is in the simple conditional tense (“would like”). When this is the case, the other verb is in the simple present tense (“has”).
The sentence would also be correct if written this way: “I would have liked to live in a house that had five rooms.” Here the first verb is in the perfect conditional (“would have liked”), and when this is the case, the other verb is in the simple past tense (“had”).
Here’s how to use “like,” in the (1) present, (2) past, (3) future, and (4) conditional:
Simple: I like … I liked … I will like … I would like.
Progressive: I am liking … I was liking … I will be liking … I would be liking.
Perfect: I have liked … I had liked … I will have liked … I would have liked.
English speakers use the subjunctive mood (instead of the normal indicative mood) on three occasions:
(1) When expressing a wish: “I wish I were taller.” [Not: "I wish I was taller."]
(2) When expressing an “if” statement about a condition that’s contrary to fact: “If I were king …” [Not: "If I was king ..."]
(3) When something is asked, demanded, ordered, suggested, and so on: “I suggest he get a job.” [Not: "I suggest he gets a job."]