Sorry for my late response,I just read your email.Order A will be ready on 12/3,but don't have news about Order B so far,please kindly be informed.因为是英文邮件,所以要写得简短点,又要符合老外的表达习...
Sorry, we received your e-mail just now. The goods as per the order A will be finished on Dec.3rd 2013. By the way, we know nothing about the order B, please advice, thanks!