A reader submitted three queries about which verb forms to use to indicate various tenses. Here are the questions and my responses.
1. When do you use have with another verb, and when do you omit it? (For example, “I have said yesterday . . .” vs. “I said yesterday . . . .”) When do you use had? (“I had said yesterday . . . .”)
“I have said yesterday . . .” is erroneous. Use have in this type of construction only when you want to emphasize that the action occurred at an unspecified time: “I have said that I would support the policy.” (This form is called the present perfect tense.) Use had for the past perfect tense, when you want to indicate that something happened before a previous occurrence or a previous time: “I had said that I would support the policy, but that was before I realized it is unfair.”
2. When should I use would as in “I would want to eat there,” as opposed to “I want to eat there”? What is the difference?
“I would want to eat there” implies or precedes a condition: “I would want to eat there if it weren’t so expensive.” “I want to eat there,” by contrast, expresses a simple desire.
3. What’s the difference between “If I can, then I will” and “If I could, then I would”?
“If I can, then I will” expresses a simple desire to accommodate. “If I could, then I would” implies that, because of a condition that is unnamed or not yet named, one is unable to accommodate.