Beginning PHP - Challenge help

I am a little confused. I new to programming and have been hung up on the String Function Challenge (21) "Display number of characters removed from string." I finally got it...after ignoring a few weird results. But I was still puzzled as to why my phrase or sentence did not display leading and trailing blank spaces even before I added the function TRIM?

$phrase = " this is my phrase ";
print $phrase;

displayed:

this is my phrase

I felt it should display:

_ _ _ _ _ this is my phrase_ _ _ _ _ (the underscore indicates the spaces but would really print to the screen as indented)

Am I correct with this? If yes how do you print a phrase with leading and trailing spaces?

Thanks for any help.