Thank you so much DoctorOhh. However, I'm having issue with the conversion, not calibre viewer. I even tried to open the PDF with newest Adobe Reader X and Nitro PDF Pro. The PDF file got cut for the last character as the picture shown. This happen for a few EPUB input files, could it be a font issue? I tried to set the margin right but still no luck.
And the problem with PDF links. I'm using newest 0.9.27. So far here I have 2/5 EPUB files that have problem with links after converted to PDF. And again, I tried with several PDF readers already, so it's not the problem with Calibre Viewer. The output PDF file just doesn't have links

even the EPUB does. This's really weird.
Again, I really appreciate your help.