"I Don't Recall"

It's easy to get sloppy when asking questions, but there's a big difference between asking a witness whether "they recall" something and asking whether it happened. Likewise, if a witness starts answering questions by saying that she "does not recall." follow up by asking, "So you can not say whether the light was red or green, is that correct?" If someone does not recall or you ask them if they remember something rather than whether it did or did not happen, you expose yourself to having that witness' recollection refreshed later on. It's a difference that matters.