New Post: how to let line not breaks after addtext

hi there i've got a problem that is i need to creat a string with different size of word here is example

$section->addText("               ");
$section->addText("a",array('size'=>15));
$section->addText("               ");

and what i expect is like this

          a              and with bigger "a"

but this is what really show

              
a
              
and with bigger "a" too 

so how can i concatenation few string with different size of word without line break or creat one string that can show different size of word

thanks!