Line direct below frame title in beamer presentation

In beamer, the content of one slide is middle aligned. I want to keep most of the content in this way, but put one single line direct below title. So that I can put reference or a brief describe in this line. A single line well separated with the main content.

I am a new user, I can not put image to explain where I want to put the line, I hope I am well explained.

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Welcome to TeX.sx! You don't have to sign with your name since it automatically appears in the lower right corner of your post. You could insert the image as normal (image icon on top or CTRL+G) and simply remove the ! before the inserted code. It turns the image into a link to the image, which is allowed for new users. –  Martin Scharrer Jun 29 '11 at 10:02

You could use sub-titles for this. There are automatically placed below the slide/frame title. If you don't like the sub-title style you could adjust it or use the textpos package to position text at any absolute position you want.

You can specify sub-titles using the second (optional!) { } argument of the frame environment or \frame macro or using \framesubtitle{..} inside it:

\begin{frame}{my title}{my sub-title}
...
\end{frame}

or

\begin{frame}{my title}
\framesubtitle{my sub-title}
...
\end{frame}

or

\begin{frame}
\frametitle{my title}
\framesubtitle{my sub-title}
...
\end{frame}
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Thank you, I will try textpos. I don't want to use the subtitle, because I set a background color to the frame title. But this line I want it to has same background with the frame –  chuan Jun 29 '11 at 20:42