Do I have to specify the time when I say "How silly of me!" in the past?
Let’s say I’m telling a friend about something silly that I did in the past, and I say:
How silly of me (it was) not to suspect that!
Is "it was" implicit in this case—since my friend understands that I’m telling him about a past experience—or do I strictly have to add it?
Please note, I know that I could say:
It was silly of me not to suspect that
But I want to maintain the first sentence structure.
I found a mind-boggling number of results for "How silly of me not to do X" and the context in all of them is about the past. Here are a few examples:
How silly of me not to recognize him.
How silly of me not to remember you.
How silly of me not to realize that.
How silly of me not to take care of it.
How silly of me not to have planned ahead.
When I have Google Translate translate them into Persian as stand-alone sentences, it translates them using the present tense, so it seems that if there is context, the "it was" is implicit and there’s no need to mention it, but if it’s a stand-alone sentence out of context, we’d better use "it was" to remove any and all doubt.