Centering Lines

Here's the LaTeX input for the poem.tex file. Notice the two backslashes after the word "white," which breaks the line in the proper place.

     Alice felt that in that case she really {\em ought} 
     to listen to it, so she sat down, and said 
     ``Thank you'' rather sadly.
     \begin{center}
     ``In winter, when the fields are white, \\ 
     I sing this song for your delight -- 
     \end{center}
     only I don't sing it,'' he added, as an
     explanation.

Note also that in the dvi output, the lines are centered, but they do not line up on the left.