Sorry to keep asking questions, I'm having issues with BiBteX again

I just wondered if anyone could help. I have a bibliography using the plain bibliography style. The titles of articles do not have capital letters in the final document except the first letter of each. This is good in the main, except on one title there are two sentences with a question mark "blahblah? blahblah". It looks a bit weird that the second sentence doesn't start with a capital, even if you put it in the bib file with a capital. Hope this make sense.
Thanks again for any help